Answer
$m=144$
Work Step by Step
The given equation is
$\Rightarrow 7=\sqrt{m}-5$
Add $5$ to each side.
$\Rightarrow 7+5=\sqrt{m}-5+5$
Simplify.
$\Rightarrow 12=\sqrt{m}$
Square each side of the equation.
$\Rightarrow 12^2=(\sqrt{m})^2$
Simplify.
$\Rightarrow 144=m$
Check $m=144$.
$\Rightarrow 7=\sqrt{m}-5$
$\Rightarrow 7=\sqrt{144}-5$
$\Rightarrow 7=12-5$
$\Rightarrow 7=7$
True.
Hence, the solution is $m=144$.
