You incorrectly tried to add 3 to both sides of the first inequality before dividing both sides by $\displaystyle-{2}\usepackage{cmbright}\Huge\$ . You need to subtract 3 from both sides first. You also incorrectly tried to subtract 1 from each side of the second inequality before dividing both sides by $\displaystyle-{1}\usepackage{cmbright}\Huge\$ . You need to add 1 to both sides first. The correct answer is $\displaystyle{b}\le{4}\usepackage{cmbright}\Huge\$ or $\displaystyle{b}\ge{9}\usepackage{cmbright}\Huge\$ .