You probably correctly rewrote the fractions using the LCD, but made a mistake simplifying the expression in the last step. When subtracting $\displaystyle\frac{{{5}{y}+{45}}}{{{\left({y}-{9}\right)}{\left({y}+{9}\right)}}}\usepackage{cmbright}\Huge\$ , be sure to distribute the minus sign to $\displaystyle{5}{y}\usepackage{cmbright}\Huge\$ and 45. You added the $\displaystyle{5}{y}\usepackage{cmbright}\Huge\$ and the 45. The correct answer is: $\displaystyle\frac{{{9}{{y}}^{{2}}-{32}{y}-{45}}}{{{\left({y}+{9}\right)}{\left({y}-{9}\right)}}}\usepackage{cmbright}\Huge\$