Quadratic function vertex and points

Using the vertex form $f(x) = a(x-h)^2 + k$, substitute the vertex $(-1, 9)$ to get $f(x) = a(x+1)^2 + 9$. Then use point $(0, 7)$ to solve for $a$: $7 = a(0+1)^2 + 9 \implies 7 = a + 9 \implies a = -2$. Thus, $f(x) = -2(x+1)^2 + 9 = -2(x^2 + 2x + 1) + 9 = -2x^2 - 4x - 2 + 9 = -2x^2 - 4x + 7$.