You correctly factored 45 into $\displaystyle{9}\cdot{5}\usepackage{cmbright}\Huge\$ and took the square root of 9 to get a coefficient of 3 in front of the radical, leaving the simplified factor $\displaystyle\sqrt{{{5}}}\usepackage{cmbright}\Huge\$ . However, you did not simplify the variable factors within the radical expression.