You may have forgotten to reverse the inequality symbol when dividing both sides of the second inequality by a negative number. The solution to the first inequality is $\displaystyle{t}<{4}\usepackage{cmbright}\Huge\$ . The solution to the second inequality is $\displaystyle{t}>-{3}\usepackage{cmbright}\Huge\$ . The solution to the compound inequality is the overlap of these two solutions.