Answer
$x=\frac{-15}{7}$
Work Step by Step
$\displaystyle \begin{array}{{>{\displaystyle}l}}
We\ have:\ ( x+2)( x-3) =( x+3)^{2}\\
\\
First,\ expand\ all\ brackets:\\
\\
( x+2)( x-3) =( x+3)^{2}\\
x^{2} -3x+2x-6=x^{2} +6x+9\\
\\
Then\ simplify:\\
x^{2} -x-6=x^{2} +6x+9\\
-6=7x+9\\
7x=-15\\
x=\frac{-15}{7}
\end{array}$