Answer
3.
Work Step by Step
${{5}^{x}}=125$
Simplify the exponent ${{5}^{x}}=125$ as follows.
$\begin{align}
& {{5}^{x}}=125 \\
& {{5}^{x}}={{5}^{3}} \\
\end{align}$
Use the principle of exponent equality and solve.
$x=3$
Check:
Substitute $x=3$ in the given equation.
$\begin{matrix}
{{5}^{3}}\overset{?}{\mathop{=}}\,125 \\
125=125 \\
\end{matrix}$
Thus, the obtained solution is correct.
