Bài ôn tập chương 1 - Số hữu tỉ

Home Toán lớp 7 - Sách KNTT Toán lớp 7 - tập 1 Ôn tập chương 1 - Số hữu tỉBài tập nâng cao

{"common":{"save":0,"post_id":"5673","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"6995","post_id":"5673","mon_id":"1158532","chapter_id":"1158544","question":"Tính di\u1ec7n tích hình thang có kích th\u01b0\u1edbc nh\u01b0 trong hình v\u1ebd<\/p><svg height=\"210\" width=\"240\"> <g><title><\/title><rect fill=\"#fff\" height=\"212\" id=\"canvas_background\" width=\"242\" x=\"-1\" y=\"-1\"><\/rect> <g display=\"none\" id=\"canvasGrid\"> <rect fill=\"url(#gridpattern)\" height=\"100%\" id=\"svg_12\" stroke-width=\"0\" width=\"100%\" x=\"0\" y=\"0\"><\/rect> <\/g> <\/g> <g><title><\/title><g id=\"svg_17\"> <g id=\"svg_9\"> <g id=\"svg_3\"> <path d=\"m18.68,136.14375l36.5625,-97l121.87501,0l36.56249,97l-195,0z\" fill=\"#56aaff\" id=\"svg_1\" stroke=\"#000\" stroke-width=\"1.5\"><\/path> <line fill=\"#56aaff\" fill-opacity=\"null\" id=\"svg_2\" stroke=\"#000\" stroke-linecap=\"null\" stroke-linejoin=\"null\" stroke-opacity=\"null\" stroke-width=\"1.5\" x1=\"55\" x2=\"55\" y1=\"39.25\" y2=\"137.25\"><\/line> <\/g> <text fill=\"#56aaff\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"15\" id=\"svg_4\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"48\" xml:space=\"preserve\" y=\"30.25\">A<\/text> <text fill=\"#56aaff\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"15\" id=\"svg_5\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"174\" xml:space=\"preserve\" y=\"32.25\">B<\/text> <text fill=\"#56aaff\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"15\" id=\"svg_6\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"8\" xml:space=\"preserve\" y=\"153.25\">D<\/text> <text fill=\"#56aaff\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"15\" id=\"svg_7\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"215\" xml:space=\"preserve\" y=\"151.25\">C<\/text> <text fill=\"#56aaff\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"15\" id=\"svg_8\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"50\" xml:space=\"preserve\" y=\"156.25\">H<\/text> <\/g> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"15\" id=\"svg_10\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"106\" xml:space=\"preserve\" y=\"22.25\">3,5 cm<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"15\" id=\"svg_11\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"67\" xml:space=\"preserve\" y=\"91.25\">3,4 cm<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"15\" id=\"svg_13\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"99\" xml:space=\"preserve\" y=\"187.25\">7,5 cm<\/text> <path d=\"m210.16005,160.86371l-3.89315,-3.5l7.00001,3.5l-7.00001,3.5l3.89315,-3.5z\" fill=\"#fff\" id=\"svg_14\" stroke=\"#000\" stroke-width=\"1.5\"><\/path> <path d=\"m21.16005,160.86371l-3.89315,-3.5l7.00001,3.5l-7.00001,3.5l3.89315,-3.5z\" fill=\"#fff\" id=\"svg_15\" stroke=\"#000\" stroke-width=\"1.5\" transform=\"rotate(180 20.76690673828125,160.86370849609375) \"><\/path> <line fill=\"none\" fill-opacity=\"null\" id=\"svg_16\" stroke=\"#000\" stroke-linecap=\"null\" stroke-linejoin=\"null\" stroke-opacity=\"null\" stroke-width=\"1.5\" x1=\"19\" x2=\"211\" y1=\"161.25\" y2=\"161\"><\/line> <\/g> <\/g> <\/svg><\/span><\/p>","options":["A.<\/strong> 18,7 ","B.<\/strong> 18,7 cm","C.<\/strong> 18,7 cm³","D.<\/strong> 18,7 cm²"],"correct":"4","level":"3","hint":"Di\u1ec7n tích hình thang b\u1eb1ng n\u1eeda t\u1ed5ng hai \u0111áy nhân v\u1edbi chi\u1ec1u cao.<\/p>","answer":"Di\u1ec7n tích hình thang ABCD là<\/p>$\\dfrac{1}{2}.(AB + CD).AH$<\/span> <\/p>= $\\dfrac{1}{2}.(3,5 + 7,5).3,4=\\dfrac{1}{2}.11.3,4=\\dfrac{11}{2}.\\dfrac{34}{10}=\\dfrac{11}{1}.\\dfrac{17}{10}=\\dfrac{187}{10}$<\/span> (cm²) = 18,7 (cm²)<\/p>\u0110áp án \u0111úng là  D.<\/strong> 18,7 cm²<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"1","date":"2022-04-10 03:54:02","option_type":"txt","len":2},{"id":"6997","post_id":"5673","mon_id":"1158532","chapter_id":"1158544","question":"Tìm n bi\u1ebft<\/p>$\\left( \\dfrac{1}{25} \\right)^{24}=\\left(\\left( \\dfrac{1}{25} \\right)^{4}\\right)^n$<\/span><\/p>\u0110áp s\u1ed1:  n = <input class=\"tim_x input_number\" tpl=\"dien_so\" type=\"text\"\/><\/p>","options":"","correct":["[\"6\"]"],"level":"3","hint":"$(x^m)^n=x^{m.n}$<\/span> .<\/p>$x^m = x^n $<\/span> khi và ch\u1ec9 khi m = n<\/p>","answer":"Ta có: <\/p>$\\left( \\dfrac{1}{25} \\right)^{24}=\\left(\\left( \\dfrac{1}{25} \\right)^{4}\\right)^n$<\/span><\/p>$\\left( \\dfrac{1}{25} \\right)^{24}=\\left( \\dfrac{1}{25} \\right)^{4.n}$<\/span><\/p>Suy ra   24 = 4n  hay  n = 24 : 4 = 6<\/p>V\u1eady n = 6.<\/p>S\u1ed1 c\u1ea7n \u0111i\u1ec1n là   6<\/span><\/p>","type":"blank","extra_type":"","time":"0","user_id":"131","test":"1","date":"2022-04-10 04:01:22"},{"id":"6998","post_id":"5673","mon_id":"1158532","chapter_id":"1158544","question":"Có bao nhiêu giá tr\u1ecb c\u1ee7a x th\u1ecfa mãn<\/p>$(x - 6^2)^2-\u200b\u200b\\dfrac{1}{25}=0$<\/span>  ?<\/p>","options":["A.<\/strong> 0","B.<\/strong> 2","C.<\/strong> 1","D.<\/strong> 3"],"correct":"2","level":"3","hint":"V\u1edbi n là s\u1ed1 l\u1ebb thì   $x^n=y^n$<\/span>   ⇒ x = y<\/p>V\u1edbi n là s\u1ed1 ch\u1eb5n thì  $x^n=y^n$<\/span>  ⇒ x = y ho\u1eb7c x = –y.<\/p>","answer":"$(x - 6^2)^2-\u200b\u200b\\dfrac{1}{25}=0$<\/span><\/p>$(x - 36)^2=\u200b\u200b\\dfrac{1}{25}$<\/span><\/p>$(x - 36)^2= \\left( \\dfrac{1}{5} \\right)^2 $<\/span><\/p>Suy ra  $x-36=\\dfrac{1}{5}$<\/span> ho\u1eb7c  $x - 36 = -\\dfrac{1}{5}$<\/span>    (vì n = 2 là s\u1ed1 ch\u1eb5n)<\/p>Tr\u01b0\u1eddng h\u1ee3p 1:  $x -36 =\\dfrac{1}{5}$<\/span> ⇒ $x = \\dfrac{1}{5} + 36=\\dfrac{1+36.5}{5}=\\dfrac{181}{5}$<\/span><\/p>Tr\u01b0\u1eddng h\u1ee3p 2:  $x - 36 = -\\dfrac{1}{5}$<\/span> ⇒ $x = -\\dfrac{1}{5} + 36 = \\dfrac{-1+36.5}{5}=\\dfrac{179}{5}$<\/span><\/p>V\u1eady có 2 giá tr\u1ecb c\u1ee7a x th\u1ecfa mãn yêu c\u1ea7u bài toán.<\/p>\u0110áp án \u0111úng là   B.<\/strong> 2<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"3","date":"2022-04-10 04:25:51","option_type":"txt","len":0}]}