Question

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* Tìm x, biết:

\(3.\left(x+5\right)^2=\frac{1}{2}\)

Answer 1

Ta có: \(3\left(x+5\right)^2=\frac{1}{2}\)

\(\Leftrightarrow\left(x+5\right)^2=\frac{1}{6}\)

\(\Leftrightarrow\left[{}\begin{matrix}x+5=\frac{1}{\sqrt{6}}\\x+5=-\frac{1}{\sqrt{6}}\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=\frac{-30+\sqrt{6}}{6}\\x=\frac{-30-\sqrt{6}}{6}\end{matrix}\right.\)

Vậy: \(x\in\left\{\frac{-30+\sqrt{6}}{6};\frac{-30-\sqrt{6}}{6}\right\}\)