Algebra problem? 10 points?

Question

Let f(x) = 5x - 1 and g(x) = x^2 + 4
Find (f ºg)(4)

Answer 1

Let f(x) = 5x - 1 and g(x) = x^2 + 4

(f ºg)(4) = f(g(4)) = f(4^2 + 4)                          [ Since g(x) = x^2 + 4 ]

                           = f(16 + 4)

                           = f(20)

                           = 5(20) - 1                           [ Since f(x) = 5x - 1 ]

                           = 100 - 1

                           = 99

 Therefore (f ºg)(4) = 99.