Question

Let f(x) = x^2 + 2, and g(x) = x + 3 ; find f(g(x))

Answer 1

f(g(x)) or ( f o g)(x)

f(x) becomes the "host" function
g(x) becomes the "client" function

so any variable in the host, becomes the client function

Answer 2

or say if
f(x) = 2x + 5
g(x) = 5x+13

so f(g(x)) will be

\(\large 2(\color{red}{5x+13})+5 \)