Math help please

Question

Let f(x)=x²+5 and g (x)=3x+4 

find (g o f)(7)

(g o f)(7)=

 

 

help me solve!!!!! Please!!

Answer 1

These are composite functions, Kayla.

 

We need to find g(f(x)). In other words, everywhere there is an x in g(x), we need to replace that x with the function f(x). We have:

 

g(f(x)) = 3(x² + 5) + 4 = 3x² + 15 + 4 = 3x² + 19

 

Now, we need to evaluate this result at x = 7

 

= 3(7)² +19 = 3(49) + 19 = 147 + 19 = 166