### Home > PC3 > Chapter 2 > Lesson 2.1.3 > Problem2-39

2-39.

​Let $f(x)=x^2+x$ and $g(x)=x+1$

1. Write an expression for $g\left(f(x)\right)$.

Substitute $(x^2+x)$ for every $x$ in the $g$ function.

2. Write an expression for $f(g(x))$.

Substitute $(x+1)$ for every $x$ in the $f$ function.

1. For what value(s) of $x$ will $f(g(x))=2$?

$x^2+3x+2=2$

Now set the equation equal to $0$ and solve.