\[\boxed{\text{874.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ (2a + b)(2a - b) = 4a² - b²\]
\[*\ = b\]
\[\textbf{б)}\ (4y - 3x)(4y + 3x) = 16y² - 9x²\]
\[*\ = 4y\]
\[\textbf{в)}\ \left( 11a^{5} - b^{4} \right)\left( b^{4} + 11a^{5} \right) = 121a^{10} - b^{8}\]
\[*\ = 11a^{5}\]
\[\textbf{г)}\ m^{4} - 225c^{10} = (m^{2} - 15c^{5})(m^{2} + 15c^{5})\]
\[*\ = 15c^{5}\]