22. \(\left(\frac{1}{3}y-2\right)^2\)

\(\left(\frac{1}{3}y-2\right)^2=\left(\frac{y}{3}\right)^2-2\cdot\frac{y}{3}\cdot2+2^2=\frac{y^2}{9}-\frac{4y}{3}+4\).

Ответ: \(\frac{y^2}{9}-\frac{4y}{3}+4\).