Answer
The equation $|ax + b|=c$ will have one solution when $\color{blue}c\color{blue}=\color{blue}0$.
Work Step by Step
An absolute value equation of the form $|ax+b|=c$ will have one solution when $c=0$.
For example:
$|2x+2|=0
\\2x+2=0
\\2x=-2
\\x=-1$
