Mark M. answered 07/23/20
Retired math prof. Very extensive Precalculus tutoring experience.
A quadratic function (parabolic graph) can be expressed as f(x) = a(x - h)2 + k, where (h,k) is the vertex.
So, for the given function, we have f(x) = a(x + 1)2 + 5.
Since (-3,-3) is on the graph, f(-3) = -3.
So, -3 = a(-2)2 + 5.
Therefore, a = -2.
f(x) = -2(x + 1)2 + 5