You may have been thinking about the reciprocal of $\displaystyle-\frac{{5}}{{9}}\usepackage{cmbright}\Huge\$ , but remember that the identity property of 1 states that $\displaystyle{x}{\left({1}\right)}={x}\usepackage{cmbright}\Huge\$ , so multiplying $\displaystyle-\frac{{5}}{{9}}\usepackage{cmbright}\Huge\$ by 1 does not change its value. The correct answer is $\displaystyle-\frac{{5}}{{9}}\usepackage{cmbright}\Huge\$ .