Liên hệ giữa thứ tự và phép cộng, thứ tự và phép nhân
{"segment":[{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["<"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"$4 + (-5)$ _input_ $8 + (-5)$","hint":"","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$4 < 8$ $\\Rightarrow 4 + (-5) < 8 + (-5)$<br\/>V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 <span class='basic_pink'>\"<\"<\/span><\/span>"}]}],"id_ques":1051},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[[">"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"$12 + (-15)$ _input_ $8 + (-15)$","hint":"","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$12 > 8$ $\\Rightarrow 12 + (-15) > 8 + (-15)$<br\/>V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 <span class='basic_pink'>\">\"<\/span><\/span>"}]}],"id_ques":1052},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"<b>H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang<\/b> ","select":[" A. $6.(-4) > 5.(-4)$"," B. $(-2).(-4) > (-5).(-4)$","C. $(-12).(-9) < (-9).(-15)$ ","D. $59.(-8) > 53.(-8)$"],"hint":" Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 \u00e2m ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi ng\u01b0\u1ee3c chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho.","explain":"<span class='basic_left'>+ \u0110\u00e1p \u00e1n $A$ sai v\u00ec: $6 > 5 \\Rightarrow 6.(-4) < 5.(-4)$<br\/>+ \u0110\u00e1p \u00e1n $B$ sai v\u00ec: $-2 > -5 \\Rightarrow (-2).(-4) < (-5).(-4)$<br\/>+ \u0110\u00e1p \u00e1n $C$ <b>\u0111\u00fang<\/b> v\u00ec: $-12 > -15 \\Rightarrow (-12).(-9) < (-9).(-15)$<br\/>+ \u0110\u00e1p \u00e1n $D$ sai v\u00ec: $59 > 53 \\Rightarrow 59.(-8) < 53.(-8)$<\/span>","column":2}]}],"id_ques":1053},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"<b>H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang<\/b> ","select":[" A. $8.(-9) > 5.(-9)$"," B. $(-20).(-6) > (-25).(-6)$","C. $(-18).(-9) < (-9).(-15)$ ","D. $27.(-8) > 30.(-8)$"],"hint":" Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 \u00e2m ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi ng\u01b0\u1ee3c chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho.","explain":"<span class='basic_left'>+ \u0110\u00e1p \u00e1n $A$ sai v\u00ec: $8 > 5 \\Rightarrow 8.(-9) < 5.(-9)$<br\/>+ \u0110\u00e1p \u00e1n $B$ sai v\u00ec: $-20 > -25 \\Rightarrow (-20).(-6) < (-25).(-6)$<br\/>+ \u0110\u00e1p \u00e1n $C$ sai v\u00ec: $-18 < -15 \\Rightarrow (-18).(-9) > (-9).(-15)$<br\/>+ \u0110\u00e1p \u00e1n $D$ <b>\u0111\u00fang<\/b> v\u00ec: $27 < 30 \\Rightarrow 27.(-8) > 30.(-8)$<\/span>","column":2}]}],"id_ques":1054},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"Cho $m > n$. H\u00e3y so s\u00e1nh $2 + m$ v\u00e0 $2 + n$.","select":[" A. $2 + m > 2 + n$"," B. $2 + m < 2 + n$","C. $2 + m = 2 + n$"],"hint":" Khi c\u1ed9ng c\u00f9ng m\u1ed9t s\u1ed1 v\u00e0o c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$ m > n \\Rightarrow m + 2 > n + 2$ <br\/>Hay $2 + m > 2 + n$<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. $2 + m > 2 + n$<\/span><\/span>","column":3}]}],"id_ques":1055},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"Cho $m > n$. H\u00e3y so s\u00e1nh $5 + m$ v\u00e0 $5 + n$.","select":[" A. $5 + m > 5 + n$"," B. $5 + m < 5 + n$","C. $5 + m = 5 + n$"],"hint":" Khi c\u1ed9ng c\u00f9ng m\u1ed9t s\u1ed1 v\u00e0o c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$ m > n \\Rightarrow m + 5 > n + 5$ <br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. $5 + m > 5 + n$<\/span><\/span>","column":3}]}],"id_ques":1056},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"So s\u00e1nh $m$ v\u00e0 $n$ bi\u1ebft: $m - n = 5$.","select":[" A. $m > n$"," B. $m < n$","C. $m = n$"],"hint":"","explain":"<span class='basic_left'>Ta c\u00f3: $m - n = 5 \\Rightarrow m = n + 5$<br\/>L\u1ea1i c\u00f3: $n + 5 > n \\forall n \\in R$<br\/>$\\Rightarrow m > n$<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. $m > n$<\/span> <\/span><\/span>","column":3}]}],"id_ques":1057},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"S\u1ed1 $a$ l\u00e0 s\u1ed1 \u00e2m hay s\u1ed1 d\u01b0\u01a1ng n\u1ebfu: $12a < 18a$","select":[" A. S\u1ed1 d\u01b0\u01a1ng"," B. S\u1ed1 \u00e2m"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 d\u01b0\u01a1ng ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1eaft \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 \u00e2m ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi ng\u01b0\u1ee3c chi\u1ec1u v\u1edbi b\u1eaft \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: $12 < 18$, m\u00e0 $12a < 18a$<br\/>$\\Rightarrow a$ l\u00e0 s\u1ed1 d\u01b0\u01a1ng<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. S\u1ed1 d\u01b0\u01a1ng<\/span>","column":2}]}],"id_ques":1058},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"S\u1ed1 $a$ l\u00e0 s\u1ed1 \u00e2m hay s\u1ed1 d\u01b0\u01a1ng n\u1ebfu: $-2a < -5a$","select":[" A. S\u1ed1 d\u01b0\u01a1ng"," B. S\u1ed1 \u00e2m"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 d\u01b0\u01a1ng ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1eaft \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 \u00e2m ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi ng\u01b0\u1ee3c chi\u1ec1u v\u1edbi b\u1eaft \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: $-2 > -5$, m\u00e0 $-2a < -5a$<br\/>$\\Rightarrow a$ l\u00e0 s\u1ed1 \u00e2m<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>B. S\u1ed1 \u00e2m<\/span>","column":2}]}],"id_ques":1059},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u th\u00edch h\u1ee3p (>,<,=) v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["<"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"<span class='basic_left'>Cho $a < b$, h\u00e3y so s\u00e1nh $3a + 1$ v\u00e0 $3b + 1$.<br\/><b>\u0110\u00e1p \u00e1n:<\/b> $3a + 1$ _input_ $3b + 1$<\/span>","hint":"So s\u00e1nh $3a$ v\u00e0 $3b$ t\u1eeb \u0111\u00f3 so s\u00e1nh $3a + 1$ v\u00e0 $3b + 1$.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$a < b$ $\\Rightarrow 3a < 3b \\Rightarrow 3a + 1 < 3b + 1$<br\/>V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 <span class='basic_pink'>\"<\"<\/span><\/span>"}]}],"id_ques":1060},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u th\u00edch h\u1ee3p (>,<,=) v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[[">"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"<span class='basic_left'>Cho $a > b$, h\u00e3y so s\u00e1nh $a + 3$ v\u00e0 $b + 3$.<br\/><b>\u0110\u00e1p \u00e1n:<\/b> $a + 3$ _input_ $b + 3$<\/span>","hint":"Khi c\u1ed9ng c\u00f9ng m\u1ed9t s\u1ed1 v\u00e0o c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$ a > b \\Rightarrow a + 3 > b + 3$<br\/>V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 <span class='basic_pink'>\">\"<\/span><\/span>"}]}],"id_ques":1061},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u th\u00edch h\u1ee3p (>,<,=) v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["<"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai25/lv1/img\/4.jpg' \/><\/center><br\/>$1,84$ _input_ $2,54$","hint":"","explain":"Ta c\u00f3: $1,84 < 2,54$<br\/>V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 <span class='basic_pink'> \"<\"<\/span>"}]}],"id_ques":1062},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u th\u00edch h\u1ee3p (>,<,=) v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[[">"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai25/lv1/img\/5.jpg' \/><\/center><br\/>$-3,5$ _input_ $-4,5$","hint":"","explain":"Ta c\u00f3: $-3,5 > -4,5$<br\/>V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 <span class='basic_pink'> \">\"<\/span>"}]}],"id_ques":1063},{"time":24,"part":[{"title":"Ch\u1ecdn <u>nh\u1eefng<\/u> \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"Ch\u1ecdn \u0111\u01b0\u1ee3c nhi\u1ec1u \u0111\u00e1p \u00e1n","temp":"checkbox","correct":[["1","2","4"]],"list":[{"point":10,"img":"","ques":"Cho hai s\u1ed1 $a$ v\u00e0 $b$ m\u00e0 $-5a > -5b$<br\/><b> H\u00e3y ch\u1ecdn nh\u1eefng \u0111\u00e1p \u00e1n \u0111\u00fang.<\/b>","hint":"S\u1eed d\u1ee5ng quy t\u1eafc c\u1ed9ng v\u00e0 nh\u00e2n c\u1ea3 hai v\u1ebf b\u1eaft \u0111\u1eb3ng th\u1ee9c cho c\u00f9ng m\u1ed9t s\u1ed1.","column":2,"number_true":2,"select":["A. $4a < 4b$","B. $-3a > -3b$","C. $5a > 5b$","D. $-8a > -8b$"],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi c\u1ed9ng c\u00f9ng m\u1ed9t s\u1ed1 v\u00e0o c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a b\u00e2t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 d\u01b0\u01a1ng ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 \u00e2m ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi ng\u01b0\u1ee3c chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/><span class='basic_left'>+ \u0110\u00e1p \u00e1n A \u0111\u00fang v\u00ec: $-5a > -5b$ v\u00e0 $\\dfrac{1}{-5} < 0 \\Rightarrow -5a.\\dfrac{1}{-5} < -5b.\\dfrac{1}{-5} \\Rightarrow a < b \\Rightarrow 4a < 4b$<br\/>+ \u0110\u00e1p \u00e1n B \u0111\u00fang v\u00ec: $-5a > -5b $ v\u00e0 $\\dfrac{1}{-5} < 0 \\Rightarrow -5a.\\dfrac{1}{-5} < -5b.\\dfrac{1}{-5} \\Rightarrow a < b \\Rightarrow -3a > -3b$<br\/>+ \u0110\u00e1p \u00e1n C sai v\u00ec: $-5a > -5b$ v\u00e0 $\\dfrac{1}{-5} < 0 \\Rightarrow -5a.\\dfrac{1}{-5} < -5b.\\dfrac{1}{-5} \\Rightarrow a < b \\Rightarrow 5a < 5b$<br\/>+ \u0110\u00e1p \u00e1n D \u0111\u00fang v\u00ec: $-5a > -5b$ v\u00e0 $\\dfrac{1}{-5} < 0 \\Rightarrow -5a.\\dfrac{1}{-5} < -5b.\\dfrac{1}{-5} \\Rightarrow a < b \\Rightarrow -8a > -8b$<\/span>"}]}],"id_ques":1064},{"time":24,"part":[{"title":"Ch\u1ecdn <u>nh\u1eefng<\/u> \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"Ch\u1ecdn \u0111\u01b0\u1ee3c nhi\u1ec1u \u0111\u00e1p \u00e1n","temp":"checkbox","correct":[["1","3","4"]],"list":[{"point":10,"img":"","ques":"Cho hai s\u1ed1 $a$ v\u00e0 $b$ m\u00e0 $6a > 6b$<br\/><b> H\u00e3y ch\u1ecdn nh\u1eefng \u0111\u00e1p \u00e1n \u0111\u00fang.<\/b>","hint":"S\u1eed d\u1ee5ng quy t\u1eafc c\u1ed9ng v\u00e0 nh\u00e2n c\u1ea3 hai v\u1ebf b\u1eaft \u0111\u1eb3ng th\u1ee9c cho c\u00f9ng m\u1ed9t s\u1ed1.","column":2,"number_true":2,"select":["A. $a + 1 > b + 1$","B. $5a < 5b$","C. $a - 1 > b - 1$","D. $-10a < -10b$"],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi c\u1ed9ng c\u00f9ng m\u1ed9t s\u1ed1 v\u00e0o c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a b\u00e2t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 d\u01b0\u01a1ng ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 \u00e2m ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi ng\u01b0\u1ee3c chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/><span class='basic_left'>+ \u0110\u00e1p \u00e1n A \u0111\u00fang v\u00ec: $6a > 6b$ v\u00e0 $\\frac{1}{6} > 0 \\Rightarrow 6a.\\dfrac{1}{6} > 6b.\\dfrac{1}{6} \\Rightarrow a > b \\Rightarrow a + 1 > b + 1$<br\/>+ \u0110\u00e1p \u00e1n B sai v\u00ec: $6a > 6b$ v\u00e0 $\\dfrac{1}{6} > 0 \\Rightarrow 6a.\\dfrac{1}{6} > 6b.\\dfrac{1}{6} \\Rightarrow a > b \\Rightarrow 5a > 5b$<br\/>\u0110\u00e1p \u00e1n C \u0111\u00fang v\u00ec: $6a > 6b $ v\u00e0 $\\dfrac{1}{6} > 0 \\Rightarrow 6a.\\frac{1}{6} > 6b.\\dfrac{1}{6} \\Rightarrow a > b \\Rightarrow a + (-1) > b + (-1)$ hay $a - 1 > b - 1$<br\/>+ \u0110\u00e1p \u00e1n D \u0111\u00fang v\u00ec: $6a > 6b $ v\u00e0 $\\dfrac{1}{6} > 0 \\Rightarrow 6a.\\dfrac{1}{6} > 6b.\\dfrac{1}{6} \\Rightarrow a > b \\Rightarrow -10a < -10b$<\/span><\/span> <br\/>"}]}],"id_ques":1065},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai25/lv1/img\/3.jpg' \/><\/center><br\/>Cho $a > 4$, h\u00e3y cho bi\u1ebft b\u1ea5t \u0111\u1eb3ng th\u1ee9c n\u00e0o x\u1ea3y ra:","select":[" A. $a + 5 > 8$"," B. $a + 7 < 10$","C. $-a > -4$","D. $4a < 16$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi c\u1ed9ng c\u00f9ng m\u1ed9t s\u1ed1 v\u00e0o c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho <br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 d\u01b0\u01a1ng ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1eaft \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>+ \u0110\u00e1p \u00e1n A \u0111\u00fang v\u00ec: $a > 4 \\Rightarrow a + 5 > 4 + 5 \\Rightarrow a + 5 > 9$ m\u00e0 $9 > 8$ $\\Rightarrow a + 5 > 8$<br\/>+ \u0110\u00e1p \u00e1n B sai v\u00ec: $a > 4 \\Rightarrow a + 7 > 4 + 7 \\Rightarrow a + 5 > 11$ <br\/>+ \u0110\u00e1p \u00e1n C sai v\u00ec: $a > 4$ v\u00e0 $-1 < 0$ $\\Rightarrow a.(-1) < 4.(-1)$ hay $-a < -4$<br\/>+ \u0110\u00e1p \u00e1n D sai v\u00ec: $a > 4$ v\u00e0 $4 > 0$ $\\Rightarrow a.4 > 4.4$ hay $4a < 16$ <br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. $a + 5 > 8$<\/span>","column":2}]}],"id_ques":1066},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai25/lv1/img\/4.jpg' \/><\/center><br\/>Cho $a > -3$, h\u00e3y cho bi\u1ebft b\u1ea5t \u0111\u1eb3ng th\u1ee9c n\u00e0o x\u1ea3y ra:","select":[" A. $-3a > 9$"," B. $-5a < 15$","C. $a + 3 < 0$","D. $-a > 3$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi c\u1ed9ng c\u00f9ng m\u1ed9t s\u1ed1 v\u00e0o c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho <br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 d\u01b0\u01a1ng ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1eaft \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<br\/>+ Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 \u00e2m ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi ng\u01b0\u1ee3c chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>+ \u0110\u00e1p \u00e1n A sai v\u00ec: $a > -3$ v\u00e0 $-3 < 0 \\Rightarrow a.(-3) < (-3).(-3) \\Rightarrow -3a < 9$<br\/>+ \u0110\u00e1p \u00e1n B \u0111\u00fang v\u00ec: $a > -3$ v\u00e0 $-5 < 0 \\Rightarrow a.(-5) < (-3).(-5) \\Rightarrow -5a < 15$ <br\/>+ \u0110\u00e1p \u00e1n C sai v\u00ec: $a > -3 \\Rightarrow a + 3 > (-3) + 3 \\Rightarrow a + 3 > 0$<br\/>+ \u0110\u00e1p \u00e1n D sai v\u00ec: $a > -3$ v\u00e0 $-1 < 0$ $\\Rightarrow a.(-1) < (-3).(-1)$ hay $-a < 3$ <br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>B. $-5a < 15$<\/span>","column":2}]}],"id_ques":1067},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":" Khi c\u1ed9ng c\u00f9ng m\u1ed9t s\u1ed1 v\u00e0o c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi ............ v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho<br\/><b>H\u00e3y ch\u1ecdn c\u1ee5m t\u1eeb th\u00edch h\u1ee3p \u0111i\u1ec1n v\u00e0o ch\u1ed7 tr\u1ed1ng <\/b>","select":[" A. Ng\u01b0\u1ee3c chi\u1ec1u"," B. C\u00f9ng chi\u1ec1u"],"hint":"","explain":"\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'>B. C\u00f9ng chi\u1ec1u<\/span>","column":2}]}],"id_ques":1068},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" Khi nh\u00e2n c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c v\u1edbi c\u00f9ng m\u1ed9t s\u1ed1 \u00e2m ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi .............. v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho <br\/><b>H\u00e3y ch\u1ecdn c\u1ee5m t\u1eeb th\u00edch h\u1ee3p \u0111i\u1ec1n v\u00e0o ch\u1ed7 tr\u1ed1ng <\/b>","select":[" A. Ng\u01b0\u1ee3c chi\u1ec1u"," B. C\u00f9ng chi\u1ec1u"],"hint":"","explain":"\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'>A. Ng\u01b0\u1ee3c chi\u1ec1u<\/span>","column":2}]}],"id_ques":1069},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai25/lv1/img\/4.jpg' \/><\/center><br\/>Cho $x < y$, h\u00e3y so s\u00e1nh: $x - y$ v\u00e0 $0$.","select":[" A. $x - y > 0$"," B. $x - y = 0$","C. $x - y < 0$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi c\u1ed9ng c\u00f9ng m\u1ed9t s\u1ed1 v\u00e0o c\u1ea3 hai v\u1ebf c\u1ee7a m\u1ed9t b\u1ea5t \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c m\u1edbi c\u00f9ng chi\u1ec1u v\u1edbi b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 cho <\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: <br\/>$x < y \\Rightarrow x + (-y) < y + (-y) \\Rightarrow x - y < 0$<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>C. $x - y < 0$<\/span>","column":3}]}],"id_ques":1070}],"lesson":{"save":0,"level":1}}