Correct. $\displaystyle{\left({5}{y}+{11}\right)}{\left({5}{y}-{11}\right)}\usepackage{cmbright}\Huge\$ results in $\displaystyle{25}{{y}}^{{2}}-{55}{y}+{55}{y}-{121}\usepackage{cmbright}\Huge\$ . The two middle terms cancel, resulting in a two-term polynomial. This expression is an example of the product of a sum and a difference, which has the general form $\displaystyle{\left({a}+{b}\right)}{\left({a}-{b}\right)}={{a}}^{{2}}-{{b}}^{{2}}\usepackage{cmbright}\Huge\$ .