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Home Lớp 7 Toán lớp 7 - Sách kết nối tri thức Bài 23: Đại lượng tỉ lệ nghịchBài tập cơ bản

{"common":{"save":0,"post_id":"5797","level":1,"total":10,"point":10,"point_extra":0},"segment":[{"id":"8277","post_id":"5797","mon_id":"1158532","chapter_id":"1158659","question":"\u0110\u1ea1i l\u01b0\u1ee3ng y liên h\u1ec7 v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng x theo công th\u1ee9c nào d\u01b0\u1edbi \u0111ây thì ta nói y t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 $a$<\/span> ($\u200b\u200ba$<\/span> là m\u1ed9t h\u1eb1ng s\u1ed1 khác 0).<\/p>","options":["A. <\/strong>$y=a.x$<\/span>","B. <\/strong>$y=\\dfrac{a}{x}$<\/span>","C. <\/strong>$y=a+x$<\/span>","D. <\/strong>$y=a-x$<\/span>"],"correct":"2","level":"1","hint":"T\u1ec9 l\u1ec7 ngh\u1ecbch là m\u1ed1i quan h\u1ec7 gi\u1eefa hai \u0111\u1ea1i l\u01b0\u1ee3ng mà khi m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng t\u0103ng bao nhiêu l\u1ea7n thì \u0111\u1ea1i l\u01b0\u1ee3ng kia s\u1ebd gi\u1ea3m b\u1ea5y nhiêu l\u1ea7n, và ng\u01b0\u1ee3c l\u1ea1i.<\/p>","answer":"N\u1ebfu \u0111\u1ea1i l\u01b0\u1ee3ng y liên h\u1ec7 v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng x theo công th\u1ee9c $y=\\dfrac{a}{x}$<\/span><\/span> thì ta nói y t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 $\u200b\u200ba$<\/span> ($\u200b\u200ba$<\/span> là m\u1ed9t h\u1eb1ng s\u1ed1 khác 0).<\/p>\u0110áp án \u0111úng là  B. $y=\\dfrac{a}{x}$<\/span><\/strong><\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"3","date":"2022-05-28 09:09:04","option_type":"math","len":0},{"id":"8288","post_id":"5797","mon_id":"1158532","chapter_id":"1158659","question":"N\u1ebfu y t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 $a$<\/span> ($a\\ne0$<\/span>) thì x t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi y theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 <input class=\"_tit_hoi\" disabled=\"disabled\" type=\"text\"\/> và ta nói x và y là hai \u0111\u1ea1i l\u01b0\u1ee3ng t\u1ec9 l\u1ec7 ngh\u1ecbch.<\/p>","options":["$a^2$<\/span>","$\\dfrac{a}{2}$<\/span>","$a$<\/span>","$\\dfrac{1}{a}$<\/span>"],"correct":"3","level":"1","hint":"","answer":"N\u1ebfu y t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 $a$<\/span> ($a\\ne0$<\/span>) thì x t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi y theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 $a$<\/span><\/span> và ta nói x và y là hai \u0111\u1ea1i l\u01b0\u1ee3ng t\u1ec9 l\u1ec7 ngh\u1ecbch.<\/p>\u0110áp án \u0111úng là $a$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"1","date":"2022-05-28 09:34:27","option_type":"math","len":0},{"id":"8293","post_id":"5797","mon_id":"1158532","chapter_id":"1158659","question":"Cho b\u1ea3ng sau:<\/p><table border=\"1\" cellpadding=\"1\" cellspacing=\"1\" style=\"width: 500px;\"><tbody> <tr> <td>x<\/strong><\/td> <td>10<\/td> <td>8<\/td> <td>4<\/td> <td>2<\/td> <\/tr> <tr> <td>y<\/strong><\/td> <td>10<\/td> <td>12,5<\/td> <td>25<\/td> <td>50<\/td> <\/tr><\/tbody><\/table>Khi \u0111ó x và y là hai \u0111\u1ea1i l\u01b0\u1ee3ng <input class=\"_tit_hoi\" disabled=\"disabled\" type=\"text\"\/><\/p>","options":["A. <\/strong>t\u1ec9 l\u1ec7 ngh\u1ecbch","B. <\/strong>t\u1ec9 l\u1ec7 thu\u1eadn","C. <\/strong>b\u1ea5t kì","D. <\/strong>C\u1ea3 A, B, C \u0111\u1ec1u sai"],"correct":"1","level":"1","hint":"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>t\u1ee9c là $x_1.y_1=x_2.y_2=...=a$<\/span><\/p>","answer":"Xét tích hai giá tr\u1ecb t\u01b0\u01a1ng \u1ee9ng c\u1ee7a x và y ta có:<\/p>10 . 10 = 8 . 12,5 = 4 . 25 = 2 . 50 = 100<\/span><\/p>Suy ra x và y là hai \u0111\u1ea1i l\u01b0\u1ee3ng t\u1ec9 l\u1ec7 ngh\u1ecbch (theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 100)<\/p>V\u1eady \u0111áp án \u0111úng là A. <\/strong>t\u1ec9 l\u1ec7 ngh\u1ecbch<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"1","date":"2022-05-28 09:54:10","option_type":"txt","len":2}]}