So this was actually Stage 4, Lesson #7.
Maybe I made this more complicated than it needed to be, but there was quite a bit of complicated math going on here!
I wasn't sure if this was looking for a quadratic equation or an exponential equation, since the instructions mentioned both. I started with the quadratic formula, and it seems to have worked.
f(x) = ax^2 + bx + c
A. f(1) = a(1^2) + b(1) + c = 15
B. f(2) = a(2^2) + b(2) + c = 45
C. f(3) = a(3^2) + b(3) + c = 95
D. f(4) = a(4^2) + b(4) + c = 165
I solved the system of equations using:
B - 2A and C - 3A to get a two-variable system.
When all was said and done, I ended up with
a = 10, b = 0, and c = 5
So the equation is y = 10x^2 + 5