[tex]\bf \textit{parabola vertex form}\\\\
\boxed{y=a(x-{{ h}})^2+{{ k}}}\\\\
x=a(y-{{ k}})^2+{{ h}}\qquad\qquad vertex\ ({{ h}},{{ k}})\\\\
-----------------------------\\\\
y=a(x-h)^2+k\qquad
\begin{cases}
h=-2\\
k=-3
\end{cases}\implies y=a[x-(-2)]^2-3
\\\\\\
y=(x+2)^2-3[/tex]
expand the binomial, either binomial theorem, or just FOIL
bear in mind, we're assuming the coefficient "a" is 1
and we're also assuming is the first form, it could be the second, but we're assuming is a vertical parabola
