Question

If $f\left(x\right)=\{\begin{array}{c}3x+1,0\le x\le 2\\ 1+9x,2<x<3\\ 30+2x,x\ge 3\end{array}$ find
$f\left(4\right)$

Answer 1

We have to find $f\left(4\right)$, for this we use function $30+2x$ because it is defined for all value of $x$ which is greater than $3$

Put $x=4$ in function $30+2x$

$f\left(4\right)=30+2\left(4\right)$

$f\left(4\right)=30+8$

$f\left(4\right)=38$