Incorrect. For $\displaystyle{b}=-{4}\usepackage{cmbright}\Huge\$ , the quantity $\displaystyle{\left|{12}-{2}{b}\right|}\usepackage{cmbright}\Huge\$ can be written as $\displaystyle{\left|{12}-{2}{\left(-{4}\right)}\right|}\usepackage{cmbright}\Huge\$ , or $\displaystyle{\left|{12}+{8}\right|}.\usepackage{cmbright}\Huge\$ Does this help you think about the problem?