Question

When f(x)=2x^2+3, find f(-3).

Answer 1

f(-3) = 21

Explanation:

We "evaluate" the function f(x)=2x^2+3 at x = -3 by subbing -3 for x in f(x)=2x^2+3:

f(-3) = 2(-3)^2 + 3 = 2(9) + 3 = 21.

Thus, f(-3) = 21