Answer
$
y=\frac{7}{4}(x+2)^2
$
Work Step by Step
There is one zero at $x=-2$, so by symmetry the vertex is $(-2,0)$. We have $y=a(x+2)^2$. Solving for $a$, we have
$$
\begin{aligned}
a(0+2)^2 & =7 \\
4 a & =7 \\
a & =\frac{7}{4}
\end{aligned}
$$ Hence $$
y=\frac{7}{4}(x+2)^2
$$