a)(x-2/3)^2=25/36 b)(3/4-x)= 8

`#BanhMii`

Đáp án:

Giải thích các bước giải:

`a) (x - 2/3)^2 = 25/36`

`=>` $\left[\begin{matrix} (x - \dfrac{2}{3})^2 = (\dfrac{5}{6})^2\\(x - (\dfrac{2}{3})^2 = -(\dfrac{5}{6})^2\end{matrix}\right.$

`=>` $\left[\begin{matrix} x - \dfrac{2}{3} = \dfrac{5}{6}\\x -\dfrac{2}{3} = -\dfrac{5}{6}\end{matrix}\right.$

`=>` $\left[\begin{matrix} x = \dfrac{5}{6} + \dfrac{2}{3}\\x = -\dfrac{5}{6} + \dfrac{2}{3}\end{matrix}\right.$

`=>` $\left[\begin{matrix} x =\dfrac{5}{6}+\dfrac{4}{6} = \dfrac{3}{2}\\x = -\dfrac{5}{6} + \dfrac{4}{6} = -\dfrac{1}{6}\end{matrix}\right.$

Vậy: `x = 3/2` hoặc `x = -1/6`

`b) (3/4 - x)^3 = 8`

`=>` $\left[\begin{matrix} (\dfrac{3}{4}- x)^3= 2^3\\ (\dfrac{3}{4} - x)^3 =(-2)^3 \end{matrix}\right.$

`=>` $\left[\begin{matrix}\dfrac{3}{4}- x = 2\\ \dfrac{3}{4} - x = -2\end{matrix}\right.$

`=>` $\left[\begin{matrix} x = \dfrac{3}{4}- 2\\ x = \dfrac{3}{4} - (-2)\end{matrix}\right.$

`=>` $\left[\begin{matrix} x = \dfrac{3}{4}- \dfrac{8}{4} = -\dfrac{5}{4}\\ x = \dfrac{3}{4} +\dfrac{8}{4} = \dfrac{11}{4}\end{matrix}\right.$

Vậy: `x = -5/4` hoặc `x = 11/4`