{"common":{"save":0,"post_id":"5798","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"8304","post_id":"5798","mon_id":"1158532","chapter_id":"1158659","question":"<p>Cho x t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi y và y t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi z. Khi \u0111ó m\u1ed1i quan h\u1ec7 gi\u1eefa hai \u0111\u1ea1i l\u01b0\u1ee3ng x và z là?<\/p>","options":["<strong>A. <\/strong>x và z t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau","<strong>B. <\/strong>x và z t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi nhau","<strong>C. <\/strong>x và z không t\u1ec9 l\u1ec7 ngh\u1ecbch c\u0169ng không t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi nhau","<strong>D. <\/strong>Không xác \u0111\u1ecbnh \u0111\u01b0\u1ee3c"],"correct":"2","level":"2","hint":"","answer":"<p>Gi\u1ea3 s\u1eed x t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi y theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 m, suy ra <span style=\"color:#2980b9;\">x = m . y<\/span><\/p><p> y t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 n, suy ra <span style=\"color:#2980b9;\">y = n . z<\/span><\/p><p>Suy ra x = m . y = m . (n . z) hay <span style=\"color:#2980b9;\">x = (m.n) . z<\/span><\/p><p>Suy ra x t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 là m.n.<\/p><p>V\u1eady \u0111áp án \u0111úng là <span style=\"color:#16a085;\"><strong>B. <\/strong>x và z t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi nhau<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"1","date":"2022-05-28 10:35:34","option_type":"txt","len":3},{"id":"8306","post_id":"5798","mon_id":"1158532","chapter_id":"1158659","question":"<p>Cho x t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi y và y t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi z. Khi \u0111ó m\u1ed1i quan h\u1ec7 gi\u1eefa hai \u0111\u1ea1i l\u01b0\u1ee3ng x và z là?<\/p>","options":["<strong>A. <\/strong>x và z t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau","<strong>B. <\/strong>x và z t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi nhau","<strong>C. <\/strong>x và z không t\u1ec9 l\u1ec7 ngh\u1ecbch c\u0169ng không t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi nhau","<strong>D. <\/strong>Không xác \u0111\u1ecbnh \u0111\u01b0\u1ee3c"],"correct":"2","level":"2","hint":"","answer":"<p>Gi\u1ea3 s\u1eed x t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi y theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 m, suy ra <span style=\"color:#2980b9;\">x = <span class=\"math-tex\">$\\dfrac{m}{y}$<\/span><\/span><\/p><p> y t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 n, suy ra <span style=\"color:#2980b9;\">y = <span class=\"math-tex\">$\\dfrac{n}{z}$<\/span><\/span><\/p><p>Suy ra x = <span class=\"math-tex\">$\\dfrac{m}{y}=m:y$<\/span> = <span class=\"math-tex\">$m:\\dfrac{n}{z}=m.\\dfrac{z}{n}=\\dfrac{m}{n}.z$<\/span> hay <span style=\"color:#2980b9;\">x = <span class=\"math-tex\">$\\dfrac{m}{n}.z$<\/span><\/span><\/p><p>Suy ra x t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 là <span class=\"math-tex\">$\\dfrac{m}{n}$<\/span>.<\/p><p>V\u1eady \u0111áp án \u0111úng là <span style=\"color:#16a085;\"><strong>B. <\/strong>x và z t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi nhau<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"1","date":"2022-05-28 10:40:57","option_type":"txt","len":3},{"id":"8359","post_id":"5798","mon_id":"1158532","chapter_id":"1158659","question":"<p>Cho x và y là hai \u0111\u1ea1i l\u01b0\u1ee3ng t\u1ec9 l\u1ec7 ngh\u1ecbch. \u0110i\u1ec1n các s\u1ed1 thích h\u1ee3p vào ô tr\u1ed1ng trong b\u1ea3ng sau:<\/p><table border=\"1\" cellpadding=\"1\" cellspacing=\"1\" style=\"width: 750px;\"><tbody> <tr> <td><strong>x<\/strong><\/td> <td>5<\/td> <td>10<\/td> <td><input class=\"tim_x input_number\" tpl=\"dien_so\" type=\"text\"\/><\/td> <\/tr> <tr> <td><strong>y<\/strong><\/td> <td>60<\/td> <td><input class=\"tim_x input_number\" tpl=\"dien_so\" type=\"text\"\/><\/td> <td>15<\/td> <\/tr><\/tbody><\/table>","options":"","correct":["[\"20\",\"30\"]"],"level":"2","hint":"<p>N\u1ebfu hai \u0111\u1ea1i l\u01b0\u1ee3ng x và y t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau thì tích hai giá tr\u1ecb t\u01b0\u01a1ng \u1ee9ng c\u1ee7a chúng luôn không \u0111\u1ed5i (và b\u1eb1ng h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7)<\/p><p>t\u1ee9c là <span class=\"math-tex\">$x_1.y_1=x_2.y_2=...=a$<\/span><\/p>","answer":"<p>Gi\u1ea3 s\u1eed x và y t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 <span class=\"math-tex\">$a$<\/span> (<span class=\"math-tex\">$a\\ne0$<\/span>).<\/p><p>Do \u0111ó <span class=\"math-tex\">$a = x_1.y_1=5.60 = 300$<\/span>. Suy ra <span class=\"math-tex\">$y=\\dfrac{300}{x}$<\/span><\/p><p>Khi <span class=\"math-tex\">$x_2 = 10$<\/span> thì <span class=\"math-tex\">$y_2=\\dfrac{300}{10}=30$<\/span><\/p><p>Khi <span class=\"math-tex\">$y_3 = 15$<\/span> thì <span class=\"math-tex\">$15=\\dfrac{300}{x_3}$<\/span> . Suy ra <span class=\"math-tex\">$x_3 = \\dfrac{300}{15}=20$<\/span><\/p><p>V\u1eady các s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u1ea7n l\u01b0\u1ee3t là <span style=\"color:#16a085;\">20 ; 30<\/span><\/p>","type":"blank","extra_type":"","time":"0","user_id":"131","test":"3","date":"2022-05-29 03:33:07"}]}