Solve the first inequality by adding 15 to both sides and then dividing by 3 to get $\displaystyle{t}<{4}\usepackage{cmbright}\Huge\$ . Solve the second inequality by dividing both sides by $\displaystyle-{4}\usepackage{cmbright}\Huge\$ to get $\displaystyle{t}>-{3}\usepackage{cmbright}\Huge\$ . The solution $\displaystyle{t}<{4}\usepackage{cmbright}\Huge\$ and $\displaystyle{t}>-{3}\usepackage{cmbright}\Huge\$ can be rewritten as $\displaystyle-{3}<{t}<{4}\usepackage{cmbright}\Huge\$ .