\[ \left( \frac{2}{11} \right)^2 = \frac{2^2}{11^2} = \frac{4}{121} \]
\[ 33 \cdot \frac{4}{121} = \frac{33 \cdot 4}{121} = \frac{3 \cdot 11 \cdot 4}{11 \cdot 11} = \frac{3 \cdot 4}{11} = \frac{12}{11} \]
\[ 28 \cdot \frac{2}{11} = \frac{28 \cdot 2}{11} = \frac{56}{11} \]
\[ \frac{12}{11} - \frac{56}{11} = \frac{12 - 56}{11} = \frac{-44}{11} = -4 \]
Ответ: -4