`(x+1/2)^2=4/25`
`(x+1/2)^2=(2/5)^2` hoặc `(x+1/2)^2=(-2/5)^2`
`x+1/2=2/5` hoặc `x+1/2=-2/5`
`=>x=2/5-1/2` hoặc `x=-2/5-1/2`
`=>x=4/10-5/10` hoặc `x=-4/10-5/10`
`=>x=-1/10` hoặc `x=-9/10`
\(\left(x+\dfrac{1}{2}\right)^2=\dfrac{4}{25}\\ \Leftrightarrow\left[{}\begin{matrix}\left(x+\dfrac{1}{2}\right)^2=\left(-\dfrac{2}{5}\right)^2\\\left(x+\dfrac{1}{2}\right)^2=\left(\dfrac{2}{5}\right)^2\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=-\dfrac{2}{5}\\x+\dfrac{1}{2}=\dfrac{2}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{2}{5}-\dfrac{1}{2}\\x=\dfrac{2}{5}-\dfrac{1}{2}\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{9}{10}\\x=-\dfrac{1}{10}\end{matrix}\right.\)
\(\left(x+\dfrac{1}{2}\right)^2=\dfrac{4}{25}\)
\(\Rightarrow\left(x+\dfrac{1}{2}\right)^2=\left(\dfrac{2}{5}\right)^2\)
TH1: \(x+\dfrac{1}{2}=\dfrac{2}{5}\)
\(\Rightarrow x=\dfrac{2}{5}-\dfrac{1}{2}\)
\(\Rightarrow x=-\dfrac{1}{10}\)
TH2: \(x+\dfrac{1}{2}=-\dfrac{2}{5}\)
\(\Rightarrow x=-\dfrac{2}{5}-\dfrac{1}{2}\)
\(\Rightarrow x=-\dfrac{9}{10}\)
Vậy:. ..
