a)-2/3x+ 1 2/5=0,6 b)[3/2-2x]-1=25% c)3/2-2x mux2=-1/2

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1. a) $\frac{-2}{3}$ . x + 1$\frac{2}{5}$ = 0,6

   $\frac{-2}{3}$ . x = 0,6 – 1$\frac{2}{5}$

   $\frac{-2}{3}$ . x = $\frac{-4}{5}$

   x = $\frac{-4}{5}$ : $\frac{-2}{3}$

   x = $\frac{-4}{5}$ . $\frac{-3}{2}$

   x = $\frac{6}{5}$

   Vậy x = x = $\frac{6}{5}$

   b) [$\frac{3}{2}$ – 2x] – 1 = 25%

   $\frac{3}{2}$ – 2x = 25% + 1

   $\frac{3}{2}$ – 2x = $\frac{1}{4}$ + 1

   $\frac{3}{2}$ – 2x = $\frac{5}{4}$

   2x = $\frac{3}{2}$ – $\frac{5}{4}$

   2x = $\frac{1}{4}$

   x = $\frac{1}{4}$ : 2

   x = $\frac{1}{8}$

   Vậy x = $\frac{1}{8}$

   c) $\frac{3}{2}$ – 2 . $x^{2}$ = $\frac{-1}{2}$

   2 . $x^{2}$ = $\frac{3}{2}$ – $\frac{-1}{2}$

   2 . $x^{2}$ = 2

   $x^{2}$ = 2 : 2

   $x^{2}$ = 1

   \(\left[ \begin{array}{l}x=1\\x=-1\end{array} \right.\)

   Vậy x = 1 hoặc x = -1

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2. Đáp án+Giải thích các bước giải:

   `a)\ \-2/3x+ 1 2/5=0,6`$\\$`-2/3x=3/5-1 2/5`$\\$`-2/3x=-4/5`$\\$`x=(-4/5):(-2/3)`$\\$`x=6/5`

   `b)[3/2-2x]-1=25%`$\\$`3/2-2x=25%+1`$\\$`3/2-2x=5/4`$\\$`2x=3/2-5/4`$\\$`2x=1/4`$\\$`x=1/4:2`$\\$`x=1/8`

   `c)3/2-2x^2=-1/2`$\\$`2x^2=3/2+1/2`$\\$`2x^2=2`$\\$`x^2=2:2`$\\$`x^2=1`$\\$`=>`\(\left[ \begin{array}{l}x=1\\x=-1\end{array} \right.\)

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