Question

$f\left(x\right)=2x^2-7x+9$ $g\left(x\right)=4x+8$ find $fog(-1)$

Answer 1

Given that,

$f\left(x\right)=2x^2-7x+9$

and $g\left(x\right)=4x+8$

$g(-1)=4(-1)+8=-4+8=4$

$fog(-1)$

$=f\left[g\right(-1\left)\right]$

$=f\left(4\right)$

$=2(4{)}^2-7(4)+9$

$=32-28+9$

$=13$

$\therefore fog(-1)=13$