Answer
$b=-7$.
Work Step by Step
The given equation is
$\Rightarrow (b+7)^2=0$
Expand equation.
$\Rightarrow (b+7)(b+7)=0$
Use zero-product property rule.
$\Rightarrow b+7=0$ or $b+7=0$
Solve for $b$.
$\Rightarrow b=-7$ or $b=-7$
Check:-
$b=-7$
$\Rightarrow (-7+7)^2=0$
$\Rightarrow (0)^2=0$
$\Rightarrow 0=0$
True.
Hence, the solution is $b=-7$.
