Đáp án+Giải thích các bước giải:

$(x-\dfrac{1}{4})^2=4$ 

\(\left[ \begin{array}{l}(x-\dfrac{1}{4})^2=2^2\\(x-\dfrac{1}{4})^2=(-2)^2\end{array} \right.\) 

\(\left[ \begin{array}{l}x-\dfrac{1}{4}=2\\x-\dfrac{1}{4}=-2\end{array} \right.\) 

\(\left[ \begin{array}{l}x=\dfrac{9}{4}\\x=\dfrac{-7}{4}\end{array} \right.\) 

Vậy x ∈ $\dfrac{9}{4};\dfrac{-7}{4}$

$\begin{array}{c} \color{#60e6f0}{\texttt{#VN2010}} \end{array}$