During the first stage of the division process, when you subtracted $\displaystyle-{x}-{\left(-{5}{x}\right)}\usepackage{cmbright}\Huge\$ , you may have mistakenly gotten $\displaystyle-{4}{x}\usepackage{cmbright}\Huge\$ as a result, when it is actually $\displaystyle{4}{x}\usepackage{cmbright}\Huge\$ .