(-5)3.\(x^2\) = - 1125
\(x^2\) = (-1125) : (-53)
\(x^2\) = 9
\(\left[{}\begin{matrix}x=-3\\x=3\end{matrix}\right.\)
Vậy \(x\) \(\in\) {-3; 3}
\(\left(-5\right)^3.x^2=-1125\)
\(x^2=-1125:\left(-5\right)^3\)
\(x^2=-1125:\left(-125\right)\)
\(x^2=9\)
\(x^2=3^2\)
\(\Rightarrow\left\{{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)
⇒ Vậy \(x\in\left\{{}\begin{matrix}3\\-3\end{matrix}\right.\)