Question

Given the definitions of f (x) and g(x) below, find the value of (g • f)(9).

f(x) = -x +11
g(x) = 3x^2– x+ 14

Answer 1

9514 1404 393

Answer:

(g·f)(9) = 496

Explanation:

One way to do this is to find the values of g(9) and f(9).

g(9) = (3x -1)x +14 = (3(9) -1)(9) +14 = 26(9) +14 = 248

f(9) = -(9) +11 = 2

Then ...

(g·f)(9) = g(9)·f(9) = 248·2

(g·f)(9) = 496