Question

Let $f(x) = 12x^9 + x$. Find $f(3) + f(-3)$.

Answer 1

Ok, here goes: f(3) means take f(x) and plug in 3 wherever we see x. So

f(3) = 12*39 + 3 = 236196 + 3

f(3) = 236199

Likewise, f(-3) means take f(x) and plug in (-3) wherever we see x. So

f(-3) = 12*(-3)9 + (-3) = -236196 - 3

f(-3) = -236199

Putting those two things together, we get

f(3) + f(-3) = 236199 - 236199 = 0

Explanation: