You mixed up the directions of the symbols when rewriting the solution. The solution is $\displaystyle{t}<{5}\usepackage{cmbright}\Huge\$ and $\displaystyle{t}>-{4}\usepackage{cmbright}\Huge\$ . This means that the values of t are greater than $\displaystyle-{4}\usepackage{cmbright}\Huge\$ and less than 5. The compound inequality given does not say this.