Let f(x) = 2x − 5and g(x) = 5x − 2. what is (g ∘ f)(−6)?

1 Answer
Apr 4, 2018

It is given that f(x) = 2x − 5f(x)=2x5 and g(x) = 5x − 2g(x)=5x2

we know (g ∘ f)(x) = g(f(x))(gf)(x)=g(f(x))

Here,
(g ∘ f)(x) = g(2x − 5)(gf)(x)=g(2x5)

=> 5(2x − 5) − 25(2x5)2 color(white)(wwwwwwwwwwwwwwwwww ["as " color(red)(g(f(x)) = 5(f(x)) − 2)][as g(f(x))=5(f(x))2]

=> 10x − 2710x27 color(white)(wwddddwwwwwwwwwddddwwwwwww ["replace " color(red)(x=-6)][replace x=6]

=> -60 − 27 = -876027=87