Question

Find if possible, $(f\circ g)(-2)$
$f\left(x\right)=2x+1),g(x)=x^2$

• A. 7
• B. 8
• C. 9
• D. 10

Answer 1

The correct option is C 9

Since $f\left(x\right)=2x+1$ and $g\left(x\right)=x^2$ and also $\left(fog\right)\left(x\right)=f\left(g\right(x\left)\right)$.

Put $x=-2$ in $g\left(x\right)$ as shown below:

$g(-2)=(-2{)}^2$

$g(-2)=4$

Now find $f\left(4\right)$ that is:

$f\left(4\right)=2\left(4\right)+1=8+1=9$

Therefore, $\left(fog\right)(-2)=f\left(g\right(-2\left)\right)=9$