B\u00e0i 81 (trang 129 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):<\/b>\u00a0<\/span><\/p>\nGi\u1ea3i c\u00e1c b\u1ea5t Ph\u01b0\u01a1ng tr\u00ecnh sau<\/p>\n
![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/1-400.png\")
<\/p>\n
L\u1eddi gi\u1ea3i:<\/b><\/p>\n
a) log5<\/sub>(3x-1) < 1.<\/p>\n![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/2-258.png\")
<\/p>\n
B\u1ea5t Ph\u01b0\u01a1ng tr\u00ecnh <=> log5<\/sub>(3x-1) < log5<\/sub>\u20615 <=> 3x-1 < 5 <=> x < 2<\/p>\nK\u1ebft h\u1ee3p v\u1edbi \u0111i\u1ec1u ki\u1ec7n ta \u0111\u01b0\u1ee3c x < 2<\/p>\n
![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/3-137.png\")
<\/p>\n
B\u1ea5t Ph\u01b0\u01a1ng tr\u00ecnh t\u01b0\u01a1ng d\u01b0\u01a1ng:<\/p>\n
![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/4-72.png\")
<\/p>\n
K\u1ebft h\u1ee3p v\u1edbi \u0111i\u1ec1u ki\u1ec7n ta \u0111\u01b0\u1ee3c:<\/p>\n
![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/5-48.png\")
<\/p>\n
c) log0,5<\/sub>(x2<\/sup>-5x+6)\u2265 -1. \u0110i\u1ec1u ki\u1ec7n: x2<\/sup>-5x+6)> 0<\/p>\nB\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh t\u01b0\u01a1ng d\u01b0\u01a1ng v\u1edbi x2<\/sup>-5x+6 \u2264 (0,5)-1<\/sup>\u00a0<=> x2<\/sup>-5x+4 \u2264 0<\/p>\n<=> 1 \u2264 x \u2264 4<\/p>\n
K\u1ebft h\u1ee3p v\u1edbi \u0111i\u1ec1u ki\u1ec7n ta \u0111\u01b0\u1ee3c t\u1eadp nghi\u1ec7m S = [1; 2) \u222a (3; 4]<\/p>\n
C\u00e1ch kh\u00e1c: x2<\/sup>-5x+6 \u2264 (0,5)-1<\/sup><\/p>\n![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/6-25.png\")
<\/p>\n
T\u1eadp nghi\u1ec7m S = [1; 2) \u222a (3; 4]<\/p>\n
![\"Gi\u1ea3i](\"http:\/\/vietjack.com\/giai-toan-12-nang-cao\/images\/bai-81-trang-129-sgk-giai-tich-12-nang-cao-6.PNG\")
<\/p>\n
B\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh tr\u00ean t\u01b0\u01a1ng d\u01b0\u01a1ng v\u1edbi<\/p>\n
![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/7-16.png\")
<\/p>\n
T\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh l\u00e0<\/p>\n
![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/8-8.png\")
<\/p>\n
B\u00e0i 82 (trang 130 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):<\/b>\u00a0<\/span><\/p>\nGi\u1ea3i c\u00e1c b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<\/p>\n
![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/1-401.png\")
<\/p>\n
L\u1eddi gi\u1ea3i:<\/b><\/p>\n
a) \u0110\u1eb7t t=log0,5<\/sub>x-2<\/p>\nTa \u0111\u01b0\u1ee3c: t2<\/sup>+t-2 \u2264 0<\/p>\n![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/2-259.png\")
<\/p>\n
b) 2x<\/sup>+2-x+1<\/sup>-3 < 0 <=> 22x<\/sup>-3.2x<\/sup>+2<0<\/p>\n\u0110\u1eb7t t=2x<\/sup>\u00a0(t>0) ta \u0111\u01b0\u1ee3c t2<\/sup>-3t+2<0 <=> 1<t<2<\/p>\n=> 1<2x<\/sup><2 <=> 0<x<1<\/p>\nV\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a Ph\u01b0\u01a1ng tr\u00ecnh S = (0; 1)<\/p>\n
B\u00e0i 83 (trang 130 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):<\/b>\u00a0<\/span><\/p>\nGi\u1ea3i c\u00e1c b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh:<\/p>\n
a) log0,1<\/sub>(x2<\/sup>+x-2)>log0,1<\/sub>(x+3)\u00a0\u00a0\u00a0 b) log1\/3<\/sub>(x2<\/sup>-6x+5)+2 log3<\/sup>(2-x) \u2265 0<\/p>\nL\u1eddi gi\u1ea3i:<\/b><\/p>\n
a) log0,1<\/sub>(x2<\/sup>+x-2)>log0,1<\/sub>(x+3)<\/p>\n![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/1-402.png\")
<\/p>\n
V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t Ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 S=(-\u221a5; -2)v\u00e0 (1;\u221a5)<\/p>\n
b) log1\/3<\/sub>(x2<\/sup>-6x+5)+2 log3<\/sup>(2-x) \u2265 0<\/p>\n![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/2-260.png\")
<\/p>\n
Ta c\u00f3: log1\/3<\/sub>(x2<\/sup>-6x+5)+2 log3<\/sup>(2-x) \u2265 0<\/p>\n<=> log1\/3<\/sub>(x2<\/sup>-6x+5)\u2265log1\/3<\/sub>(2-x)2<\/sup><\/p>\n<=> x2<\/sup>-6x+5\u2264(2-x)2<\/sup>\u00a0<=> 2x-1\u22650<\/p>\nB\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh t\u01b0\u01a1ng d\u01b0\u01a1ng v\u1edbi:<\/p>\n
![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/3-138.png\")
<\/p>\n
V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh l\u00e0:<\/p>\n
![\"\"](\"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/4-73.png\")
<\/p>\n","protected":false},"excerpt":{"rendered":"
B\u00e0i 80 (trang 129 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):\u00a0 Gi\u1ea3i c\u00e1c b\u1ea5t Ph\u01b0\u01a1ng tr\u00ecnh a) 23-6x\u00a0> 1 \u00a0\u00a0\u00a0 b) 16x\u00a0> 0,125 L\u1eddi gi\u1ea3i: a) 23-6x\u00a0> 1 <=> 23\u00a0> 26x\u00a0<=> 3 > 6x <=> x < 1\/2 b) 16x\u00a0> 0,125 <=> 24x\u00a0> 2-3\u00a0<=> 4x > -3 <=> x > -3\/4\\ B\u00e0i 81 (trang 129 sgk […]<\/p>\n","protected":false},"author":3,"featured_media":23330,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[1302],"tags":[1392,1393],"yoast_head":"\n
\u0110\u1ea1i s\u1ed1 - Ch\u01b0\u01a1ng 2 - B\u00e0i 9: B\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh m\u0169 v\u00e0 l\u00f4garit<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/lop12.edu.vn\/dai-so-chuong-2-bai-2-bat-phuong-trinh-mu-va-logarit\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"\u0110\u1ea1i s\u1ed1 - Ch\u01b0\u01a1ng 2 - B\u00e0i 9: B\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh m\u0169 v\u00e0 l\u00f4garit\" \/>\n<meta property=\"og:description\" content=\"B\u00e0i 80 (trang 129 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):\u00a0 Gi\u1ea3i c\u00e1c b\u1ea5t Ph\u01b0\u01a1ng tr\u00ecnh a) 23-6x\u00a0> 1 \u00a0\u00a0\u00a0 b) 16x\u00a0> 0,125 L\u1eddi gi\u1ea3i: a) 23-6x\u00a0> 1 <=> 23\u00a0> 26x\u00a0<=> 3 > 6x <=> x < 1\/2 b) 16x\u00a0> 0,125 <=> 24x\u00a0> 2-3\u00a0<=> 4x > -3 <=> x > -3\/4 B\u00e0i 81 (trang 129 sgk […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/lop12.edu.vn\/dai-so-chuong-2-bai-2-bat-phuong-trinh-mu-va-logarit\/\" \/>\n<meta property=\"og:site_name\" content=\"Lop12.edu.vn - 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Ch\u01b0\u01a1ng 2 - B\u00e0i 9: B\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh m\u0169 v\u00e0 l\u00f4garit","og_description":"B\u00e0i 80 (trang 129 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):\u00a0 Gi\u1ea3i c\u00e1c b\u1ea5t Ph\u01b0\u01a1ng tr\u00ecnh a) 23-6x\u00a0> 1 \u00a0\u00a0\u00a0 b) 16x\u00a0> 0,125 L\u1eddi gi\u1ea3i: a) 23-6x\u00a0> 1 <=> 23\u00a0> 26x\u00a0<=> 3 > 6x <=> x < 1\/2 b) 16x\u00a0> 0,125 <=> 24x\u00a0> 2-3\u00a0<=> 4x > -3 <=> x > -3\/4 B\u00e0i 81 (trang 129 sgk […]","og_url":"https:\/\/lop12.edu.vn\/dai-so-chuong-2-bai-2-bat-phuong-trinh-mu-va-logarit\/","og_site_name":"Lop12.edu.vn - C\u1ed9ng \u0111\u1ed3ng h\u1ecdc sinh l\u1edbp 12 l\u1edbn nh\u1ea5t t\u1ea1i Vi\u1ec7t Nam","article_published_time":"2018-03-24T04:02:19+00:00","article_modified_time":"2018-03-24T04:02:52+00:00","og_image":[{"width":255,"height":173,"url":"https:\/\/lop12.edu.vn\/wp-content\/uploads\/2018\/03\/1-400.png","type":"image\/png"}],"author":"H\u00e0 Trang","twitter_card":"summary_large_image","twitter_misc":{"Written by":"H\u00e0 Trang","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/lop12.edu.vn\/dai-so-chuong-2-bai-2-bat-phuong-trinh-mu-va-logarit\/","url":"https:\/\/lop12.edu.vn\/dai-so-chuong-2-bai-2-bat-phuong-trinh-mu-va-logarit\/","name":"\u0110\u1ea1i s\u1ed1 - 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