Question

F(x) = 3x + 10
g(x) = x - 2
Find f(g(5))

Answer 1

There are a couple ways we can solve this:

1. We can plug in g into f and then make x = 5

`3x+10\\3(x-2)+10\\3x-6+10\\3x+4\\plug.in.5\\3(5)+4\\15+4\\19`

So f(g(5)) = 19

2. We can plug in g pre-solved with x = 5 into f

`x-2\\5-2\\3\\plug.in.3.into.f\\3x+10\\3(3)+10\\9+10\\19`

So again, f(g(5)) = 19

As you can see, either way works fine. it just depends on what makes more sense to you personally.