Correct. Since $\displaystyle{{r}}^{{2}}-{2}{r}{s}+{{s}}^{{2}}={\left({r}-{s}\right)}{\left({r}-{s}\right)}\usepackage{cmbright}\Huge\$ with $\displaystyle{r}={x}\usepackage{cmbright}\Huge\$ and $\displaystyle{s}={3}\usepackage{cmbright}\Huge\$ , this is the correct answer.