{"common":{"save":0,"post_id":"963","level":2,"total":20,"point":5,"point_extra":0},"segment":[{"id":"171","post_id":"963","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":" <center><img src='img\/11.jpg' \/><\/center> Gi\u00e1 tr\u1ecb l\u1edbn nh\u1ea5t c\u1ee7a bi\u1ec3u th\u1ee9c $E = 8 - 6|x - 7| $ b\u1eb1ng: ","select":["A. $ 6 $ ","B. $ 7 $ ","C. $ 8 $ ","D. $ 1 $ "],"hint":" $E \\leq a$ th\u00ec $a$ l\u00e0 GTLN c\u1ee7a $E.$ ","explain":" Ta c\u00f3: $|x - 7| \\geq 0 \\quad \\forall x \\in \\mathbb{Q} \\\\ \\Rightarrow -6|x - 7| \\leq 0 \\\\ \\Rightarrow E = 8 - 6|x - 7| \\leq 8 $ <br\/> Do \u0111\u00f3 GTLN c\u1ee7a $E = 8$ khi $x - 7 = 0,$ t\u1ee9c l\u00e0 $x = 7$. <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C. <\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"2","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:44"},{"id":"172","post_id":"963","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":" <center><img src='img\/11.jpg' \/><\/center> Gi\u00e1 tr\u1ecb nh\u1ecf nh\u1ea5t c\u1ee7a bi\u1ec3u th\u1ee9c $M = |x - 7| + 1 - x$ b\u1eb1ng: ","select":["A. $ -5 $ ","B. $ -6 $ ","C. $ 6 $ ","D. $ 0 $ "],"hint":" $M \\geq a$ th\u00ec $a$ l\u00e0 GTNN c\u1ee7a $M.$ ","explain":" $M = |x - 7| + 1 - x$ <br\/> * N\u1ebfu $x - 7 \\geq 0 \\Leftrightarrow x \\geq 7 $ th\u00ec $M = x - 7 + 1 - x = -6 $ <br\/> * N\u1ebfu $ x < 7 $ th\u00ec $M = 7 - x + 1 - x = 8 - 2x $ <br\/> $\\quad$ V\u00ec $x < 7$ n\u00ean $ -2x > -14 \\Rightarrow M > 8 - 14 = -6$ <br\/> Nh\u01b0 v\u1eady $M \\geq -6$. Suy ra GTNN c\u1ee7a M b\u1eb1ng $-6$ khi $ x - 7 = 0$ hay $x = 7$ <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"2","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:44"},{"id":"173","post_id":"963","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"<center><img src='img\/11.jpg' \/><\/center> T\u00ecm $x$, bi\u1ebft: $ |3x - 5| - \\dfrac{1}{7} = \\dfrac{1}{3} $ ","select":["A. $ x = \\dfrac{-115}{63} $ ","B. $ x = \\dfrac{95}{63}$ ","C. $ x \\in \\left\\{ \\dfrac{115}{63}; \\dfrac{95}{63} \\right\\} $ ","D. $ x \\in \\left\\{ \\dfrac{-115}{63}; \\dfrac{95}{63} \\right\\} $ "],"explain":" Ta c\u00f3: $|3x - 5| - \\dfrac{1}{7} = \\dfrac{1}{3} \\\\ \\Leftrightarrow |3x - 5| = \\dfrac{1}{3} + \\dfrac{1}{7} = \\dfrac{10}{21} $ <br\/> Suy ra: $ 3x - 5 = \\dfrac{10}{21}$ ho\u1eb7c $3x - 5 = \\dfrac{-10}{21}$ <br\/> X\u00e9t $3x - 5 = \\dfrac{10}{21} \\Rightarrow 3x = \\dfrac{10}{21} + 5 = \\dfrac{115}{21} \\Rightarrow x = \\dfrac{115}{21} : 3 = \\dfrac{115}{63}$ <br\/> X\u00e9t $3x - 5 = \\dfrac{-10}{21} \\Rightarrow 3x = \\dfrac{-10}{21} + 5 = \\dfrac{95}{21} \\Rightarrow x = \\dfrac{95}{21} : 3 = \\dfrac{95}{63}$ <br\/> V\u1eady $ x \\in \\left\\{ \\dfrac{115}{63}; \\dfrac{95}{63} \\right\\} $ <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"2","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:44"}]}