HELP!!! Math Problem...Find the quadratic function f(x)=ax^2 +bx+c for...

Please, I need help soving this problem:

Find the quadratic function f(x)=ax^2 +bx+c for which f(1)= -2, f(-3)=54, and f(3)=6
What is the function?
f(x)=__________________________

Note that f(1) = -2, f(-3) = 54, and f(3) = 6 correspond to the points (1,-2), (-3,54), and (3,6). Plugging these into f(x) = ax² + bx + c, we get the following:
-2 = a(1)² + b(1) + c = a + b + c
54 = a(-3)² + b(-3) + c = 9a - 3b + c
6 = a(3)² + b(3) + c = 9a + 3b + c

Solve this system of equations:
-2 = a + b + c
54 = 9a - 3b + c
6 = 9a + 3b + c

After solve this you should get:
a = 3, b = -8, and c = 3

Thus:
f(x) = 3x² - 8x + 3

You create a set of simultaneous equations by putting those x, f(x) values into the standard formula:

a + b + c = -2
9a - 3b + c = 54
9a + 3b + c = 6

Use whatever method you know - substitution is fine here - to solve this set.