Correct. You combined the like terms: $\displaystyle{11}{y}+{3}{y}-{y}={\left({11}+{3}-{1}\right)}{y}={13}{y}\usepackage{cmbright}\Huge\$ , while $\displaystyle{7}{x}-{2}{x}={\left({7}-{2}\right)}{x}={5}{x}\usepackage{cmbright}\Huge\$ .