Answer
$f(x)=(x+7)(x+3)$.
Work Step by Step
If the x-intercepts of a graph are $a,b$, then the function has the form of $f(x)=k(x-a)(x-b)$. The x-intercepts are -7, -3; hence, the quadratic function becomes $f(x)=k(x+7)(x+3)$. The point (-1,12) is on the graph
Thus:
$f(x)=(x+7)(x+3)$.
