To work with an absolute value equation in algebra, you first need to rewrite it as a linear equation. The same goes for an absolute value inequality, which you rewrite as a linear inequality.
When rewriting absolute value equations or inequalities, you drop the absolute value bars.
|ax + b| = c → ax + b = c or ax + b = –c
|ax + b| > c → ax + b > c or ax + b > –c
|ax + b| < c → –c < ax + b < c