What is the solution to this equation?? Please explain steps

Let f(x)=x2+7 and g(x)= x3x
Find (fg)(3)

1 Answer
May 28, 2018

11

Explanation:

The notation is to indicate compound functions. Specifically, fg(x)=f(g(x)). To evaluate this, you sub in the value of g(x) into f(x).

fg(3)=f(g(3))=f(333)=f(2)=22+7=11

Another method to do this is to evaluate the compound function directly, and substitute in the value of -3.

fg(x)=f(g(x))=f(x3x)=(x3x)2+7.

fg(3)=(333)2+7=11