$\text{( 2x - $\dfrac{1}{2}$ )² = $\dfrac{1}{64}$}$

$\text{⇒ ( 2x - $\dfrac{1}{2}$ )² = ($\dfrac{1}{8}$)² = ($\dfrac{-1}{8}$)² }$

$\text{⇒ 2x - $\dfrac{1}{2}$ = $\dfrac{1}{8}$ = $\dfrac{-1}{8}$}$

$\text{⇒ 2x ∈ { $\dfrac{5}{8}$ ; $\dfrac{3}{8}$ } }$

$\text{⇒ x ∈ { $\dfrac{5}{16}$ ; $\dfrac{3}{16}$ } }$

$\text{Vậy x ∈ { $\dfrac{5}{16}$ ; $\dfrac{3}{16}$ } }$

`9) ( 2x - 1/2 )^2 = 1/64`

`⇒` \(\left[ \begin{array}{l}( 2x - \frac{1}{2} )^2 = ( \frac{1}{8} )^2\\( 2x - \frac{1}{2} )^2 = ( - \frac{1}{8} )^2\end{array} \right.\) 

`⇒` \(\left[ \begin{array}{l}2x - \frac{1}{2} = \frac{1}{8}\\2x - \frac{1}{2} = \frac{- 1}{8}\end{array} \right.\) 

`⇒` \(\left[ \begin{array}{l}2x = \frac{5}{8}\\2x = \frac{3}{8}\end{array} \right.\) 

`⇒` \(\left[ \begin{array}{l}x = \frac{5}{16}\\x = \frac{3}{16}\end{array} \right.\) 

Vậy `, x ∈ { 5/16 ; 3/16 } .`