Given f(x)=cx^3-9x+3$ and f(2)=9, find the value of c.
f(x) = c·x3 - 9x + 3
f(2) = 9 ---> 9 = c·(2)3 - 9(2) + 3
9 = c·8 - 18 + 3
9 = 8c - 15
24 = 8c
3 = c
