You may have forgotten to reverse the inequality symbol when dividing each side of the first inequality by $\displaystyle-{2}\usepackage{cmbright}\Huge\$ . The solution to this compound inequality is $\displaystyle{x}\ge-{2}\usepackage{cmbright}\Huge\$ or $\displaystyle{x}>{4}\usepackage{cmbright}\Huge\$ , which does not match the graph.