Question

giải PT

(-x)²=6

Answer 1

\(\left(-x\right)^2=6\)

\(\Leftrightarrow x^2=6\)

\(\Leftrightarrow x^2-6=0\)

\(\Leftrightarrow\left(x-\sqrt{6}\right)\left(x+\sqrt{6}\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-\sqrt{6}=0\\x+\sqrt{6}=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\sqrt{6}\\x=-\sqrt{6}\end{matrix}\right.\)

Vậy \(\left[{}\begin{matrix}x=\sqrt{6}\\x=-\sqrt{6}\end{matrix}\right.\)

Answer 2

\(\left(-x\right)^2=6\)

\(\Leftrightarrow x^2=6\)

\(\Leftrightarrow x=\pm\sqrt{6}\)