For the function f defined by f (x) = 3x^2 + 3x + 4, find the following values.

Question

(a) f(-9) = 220

(b) f(-x) =

(Simplify your answer.)

Answer 1

For the function f(x) = 3x² + 3x + 4, find f(-x).

To do this, just like with a numeric value, we replace all x variables with -x and evaluate:

f(-x) = 3(-x)² + 3(-x) + 4

f(-x) = 3(x²) + (-3x) + 4

f(-x) = 3x² - 3x + 4

Therefore, f(-x) = 3x² - 3x + 4.