Question

Given the functions f(x) = x + 4 and g(x) = x2 − x find the value of each expression below.

Answer 1

f(x) = x + 4

g(x) = x² - x

a) f(5)

f(5) = 5 + 4 = 9

b) g(-1)

g(-1) = (-1)² -(-1) = 1 + 1 = 2

c) f(x) = 10

10 = x + 4

x = 6

d) g(x) = 6

6 = x² - x

0 = x² - x - 6

0 = (x - 3)(x + 2)

x = 3, -2