Answer
$b=-13$.
Work Step by Step
The given equation is
$\Rightarrow (b+13)^2=0$
Expand.
$\Rightarrow (b+13)(b+13)=0$
Use zero-product property rule.
$\Rightarrow b+13=0$ or $b+13=0$
Solve for $b$.
$\Rightarrow b=-13$ or $b=-13$
Hence, the solution is $b=-13$.
