\[\boxed{\text{875.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ \left( 3x^{2} - 1 \right)\left( 3x^{2} + 1 \right) = 9x^{4} - 1\]
\[\textbf{б)}\ \left( 5a - b^{3} \right)\left( b^{3} + 5a \right) = 25a² - b^{6}\]
\[\textbf{в)}\ \left( \frac{3}{7}m^{3} + \frac{1}{4}n^{3} \right)\left( \frac{3}{7}m^{3} - \frac{1}{4}n^{3} \right) = \frac{9}{49}m^{6} - \frac{1}{16}n^{6}\]
\[\textbf{г)}\ \left( \frac{1}{15} - \frac{1}{8}p^{6} \right)\left( \frac{1}{8}p^{6} + \frac{1}{15} \right) = \frac{1}{225} - \frac{1}{64}p^{12}\]
\[\textbf{д)}\ \left( 0,4y^{3} + 5a^{2} \right)\left( 5a^{2} - 0,4y^{3} \right) = 25a^{4} - 0,16y^{6}\]
\[\textbf{е)}\ \left( 1,2c^{2} - 7a^{2} \right)\left( 1,2c^{2} + 7a^{2} \right) = 1,44c^{4} - 49a^{4}\ \]
\[\textbf{ж)}\ \left( \frac{5}{8}x + y^{5} \right)\left( y^{5} - \frac{5}{8}x \right) = y^{10} - \frac{25}{64}x²\]
\[\textbf{з)}\ \left( \frac{1}{7}p^{5} - 0,01 \right)\left( 0,01 + \frac{1}{7}p^{5} \right) = \frac{1}{49}p^{10} - 0,0001\]