Answer
$r=-5$.
Work Step by Step
The given equation is
$\Rightarrow 60=-12r$
Divide both sides by $-12$.
$\Rightarrow \frac{60}{-12}=\frac{-12r}{-12}$
Simplify.
$\Rightarrow -5=r$.
Check:-
$\Rightarrow 60=-12(5)$
$\Rightarrow 60=-60$
True.
Hence, the solution is $r=-5$.
