Answer:
D. 80
Step-by-step explanation:
Given:
f(x) = 5x - 4,
g(x) = x² - 1
Required:
(g o f)(-1)
SOLUTION:
(g o f)(-1) = g(f(-1))
Plug in -1 for x into the function, f(x) = 5x - 4:
g(f(-1)) = g(5(-1) - 4)
= g(-5 - 4)
= g(-9)
Plug in -9 for x in the function, g(x) = x² - 1
g(-9) = (-9)² - 1
= 81 - 1
= 80.
Therefore, (g o f)(-1) = g(f(-1)) = 80
D. 80 is the correct answer.
