$2$ Multiple Answer $20$ points

Consider the function $f$:$ZZ,$ defined as $f(x)=|$~$\frac{x}{2}$~$|.$ Mark each statement below only if what it says is true.

This function is onto.

This function is one$-$to$-$one.

$3$ Multiple Choice $20$ points

Let $a,$binR,$a0,$ and function $f$:$RR$ be defined by $f(x)=ax+b.$ Which of the following is true about this function's inverse?

$f$ is invertible, and $f^{-1}(x)=\frac{1}{ax+b}$

We can't say $f$ is invertible.

$f$ is invertible, and $f^{-1}(x)=\frac{x-b}{a}$

$f$ is invertible, and $f^{-1}(x)=-ax-b$