Answer
One solution if $c=0$, zero solutions if $c\lt0$ and $2$ solutions if $c\gt0$.
Work Step by Step
We know that $|ax+b|=c$ has solutions if $c$ is non-negative. In this case $ax+b=\pm c$. Thus it has one solution if $c=0$, zero solutions if $c\lt0$ and $2$ solutions if $c\gt0$.