You may have correctly multiplied the first fraction by $\displaystyle\frac{{{x}-{1}}}{{{x}-{1}}}\usepackage{cmbright}\Huge\$ and the second by $\displaystyle\frac{{{x}-{3}}}{{{x}-{3}}}\usepackage{cmbright}\Huge\$ , but then simplified the numerators incorrectly. When using the distributive property, remember to distribute the number in front of the parenthesis to both terms inside.