Question

If p(x) = 2x - 5 and r(x) = 3x + 4, calculate (pr)(x).

A
6x2 - 7x - 20
B
6x2 + 7x - 20
5x - 1
D
6x2 - 20

Answer 1

6x + 3

Explanation:

Given p(x) = 2x - 5 and r(x) = 3x + 4,

p(r(x)) = p(3x+4)

p(3x+4) = 2(3x+4) - 5

p(3x+4) = 6x + 8 - 5

p(3x+4) = 6x +3

Hence the composite function (pr)(x) is 6x + 3