Answer
$y=2(x+3)^2-10$
Work Step by Step
Vertex: $(h,k)=(-3,-10)$
Standard form:
$y=a(x-h)^2+k$
$y=a[x-(-3)]^2+(-10)$
$y=a(x+3)^2-10$
Now, use the point $(0,8)$ to find $a$:
$8=a(0+3)^2-10$
$8+10=a(9)$
$a=\frac{18}{9}=2$
$y=2(x+3)^2-10$