You may have ignored the radical signs or incorrectly thought that they canceled. Rewrite using $\displaystyle\frac{\sqrt{{a}}}{\sqrt{{b}}}=\sqrt{{\frac{{a}}{{b}}}}\usepackage{cmbright}\Huge\$ . Identify common factors in the numerator and denominator and simplify. Pull out perfect squares from $\displaystyle{8}{{x}}^{{3}}\usepackage{cmbright}\Huge\$ and simplify, using $\displaystyle\sqrt{{{a}{b}}}=\sqrt{{a}}\cdot\sqrt{{b}}\usepackage{cmbright}\Huge\$ .