Let f(x) = 7x + 2 and g(x) = x^2 − 1. Find the following below

Question

Let
f(x) = 7x + 2
and
g(x) = ^x2 − 1.
Find the following.

 

(g ∘ f)(−5)

 

Answer 1

 

  g o f = (7x+2)^2 - 1  = 49x^2 + 28x + 4 - 1 = 49x^2 + 28x + 3

 

  At x=-5 :    49 * (-5)^2 + 28*(-5) + 3 = 1088

 

 

You can also do:

f(-5) = 7(-5) + 2 = -35 + 2 = -33

 

g(-33) = (-33)^2 - 1 = 1088