Question

$f$ is a function defined by
$f\left(x\right)=\{\begin{array}{c}2x+4,x\le 2\\ 2x-1,x>2\end{array}$
Find $f\left(0\right)+f\left(2\right)+f\left(4\right)$

Answer 1

For $x\le 2,f\left(x\right)=2x+4$

$\therefore f\left(0\right)=2\left(0\right)+4=4$ and $f\left(2\right)=2\left(2\right)+4=8$

And for $x>2,f\left(x\right)=2x-1$

$\therefore f\left(4\right)=2\left(4\right)-1=7$

Hence $f\left(0\right)+f\left(2\right)+f\left(4\right)=4+8+7=19$