Question

f(x)=2x+5, g(x)=sqrt(x+4)
Find f o g

Answer 1

The meaning of f o g is f[g(x)].
That means substitute the rule of function g (which is sqrt(x+4)) into the variable in the rule of function f, thus
\[f \left( g(x) \right)=2\sqrt{x+4}+5\]

Answer 2

and what would be the answer?

Answer 3

The last line on the previous post is the answer. That is, the answer is the function "two times the square root of x plus 4, plus the constant 5."

Answer 4

" f o g" is called composition of function. You just putting one function "inside" the other. so you naturally get another function as the answer.