tìm x a) (2/5-x)^3=-8/27 b)4/3:x=3/4:2/5 c) 1/2x:8/7=0,03:4/11

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1. Đáp án:

   `a)`

   ` (2/5 -x)^3 = (-8/27) = (-2/3)^3`

   ` => 2/5 – x = -2/3`

   ` => x= 2/5 +2/3`

   ` => x= 16/15`

   `b)`

   ` 4/3 : x = 3/4 : 2/5`

   ` 4/3 : x =15/8`

   ` x =4/3 : 15/8`

   ` x  =32/45`

   `c)`

   ` 1/(2) *x : 8/7 = 0,03 * 4/11`

   `=> 1/(2) *x : 8/7 = 3/275`

   ` 1/(2) x = 24/1925`

   ` x = 48/1925`

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2. Bạn tham khảo!
   $a)$ $($ $\dfrac{2}{5}$ $-$ $x$ $)$³ $=$ $\dfrac{-8}{27}$
   $→$ $($ $\dfrac{2}{5}$ $-$ $x$ $)$³ $=$ $($ $\dfrac{2}{3}$ $)$³ và $($ $\dfrac{2}{5}$ $-$ $x$ $)$³ $=$ $($ $\dfrac{-2}{3}$ $)$³
   $→$ $\dfrac{2}{5}$ $-$ $x$ $=$ $\dfrac{2}{3}$ và $\dfrac{2}{5}$ $-$ $x$ $=$ $\dfrac{-2}{3}$
   $→$ $x$ $=$ $\dfrac{2}{5}$ $-$ $\dfrac{2}{3}$ và $x$ $=$ $\dfrac{2}{5}$ $-$ $\dfrac{-2}{3}$
   $→$ $x$ $=$ $\dfrac{-4}{15}$ và $x$ $=$ $\dfrac{16}{15}$
   $b)$ $\dfrac{4}{3}$ $:$ $x$ $=$ $\dfrac{3}{4}$ $:$ $\dfrac{2}{5}$
   $→$ $\dfrac{4}{3}$ $:$ $x$ $=$ $\dfrac{15}{8}$
   $→$ $x$ $=$ $\dfrac{4}{3}$ $:$ $\dfrac{15}{8}$
   $→$ $x$ $=$ $\dfrac{32}{45}$
   $c)$ $\dfrac{1}{2}$ $.$ $x$ $:$ $\dfrac{8}{7}$ $=$ $0.03$ $:$ $\dfrac{4}{11}$
   $→$ $\dfrac{1}{2}$ $.$ $x$ $:$ $\dfrac{8}{7}$ $=$ $\dfrac{3}{275}$
   $→$ $\dfrac{1}{2}$ $.$ $x$ $=$ $\dfrac{3}{275}$ $.$ $\dfrac{8}{7}$
   $→$ $\dfrac{1}{2}$ $.$ $x$ $=$ $\dfrac{24}{1925}$
   $→$ $x$ $=$ $\dfrac{24}{1925}$ $:$ $\dfrac{1}{2}$
   $→$ $x$ $=$ $\dfrac{12}{1925}$
   $FbBinhne2k88$

    

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