Đề kiểm tra 15 phút - Toán lớp 7 - Sách kết nối tri thức - Tháng 2

Đề kiểm tra 15 phút - Toán lớp 7 - Sách kết nối tri thức - Tháng 2 - Số 2

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{"save":1,"level":1,"time":"15","total":10,"point":5,"segment":[{"id":"10268","test_id":"688","question":"N\u1ebfu \u0111\u1ea1i l\u01b0\u1ee3ng y t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 là 3 và \u0111\u1ea1i l\u01b0\u1ee3ng x t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 là –2 thì \u0111\u1ea1i l\u01b0\u1ee3ng y t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 là<\/p>","options":["A.<\/strong> 6","B.<\/strong> –6","C.<\/strong> 5","D.<\/strong> –1"],"correct":"2","answer":"Ch\u1ecdn B.<\/strong> –6.<\/span><\/p>Vì \u0111\u1ea1i l\u01b0\u1ee3ng y t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 là 3 nên y = 3x.<\/p>Vì \u0111\u1ea1i l\u01b0\u1ee3ng x t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 là –2 nên x = –2z.<\/p>T\u1eeb \u0111ó suy ra y = 3x = 3. (–2z) = –6z.<\/p>V\u1eady \u0111\u1ea1i l\u01b0\u1ee3ng y t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 là –6<\/strong><\/span>.<\/p>","type":"choose","user_id":"126","test":"1","date":"2025-08-03 20:03:22"},{"id":"10269","test_id":"688","question":"Bi\u1ebft hai \u0111\u1ea1i l\u01b0\u1ee3ng x và y t\u1ec9 l\u1ec7 ngh\u1ecbch và khi x = 4 thì y = 12. Tính y khi x = 6.<\/p>","options":["A.<\/strong> 8","B.<\/strong> 10","C.<\/strong> 6","D.<\/strong> 12"],"correct":"1","answer":"Ch\u1ecdn A.<\/strong> 8.<\/span><\/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 là a.<\/p>Vì khi x = 4 thì y = 12 nên a = x.y = 4.12 = 48.<\/p>Do \u0111ó $y=\\dfrac{48}{x}$<\/span>.<\/p>V\u1eady khi $x=6$<\/span> thì $y=\\dfrac{48}{6}=8$<\/span>.<\/p>","type":"choose","user_id":"126","test":"2","date":"2025-08-03 20:04:16"}]}