\[\boxed{\text{873.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ \left( x^{2} - 5 \right)\left( x^{2} + 5 \right) = x^{4} - 25\]
\[\textbf{б)}\ \left( 4 + y^{2} \right)\left( y^{2} - 4 \right) = y^{4} - 16\]
\[\textbf{в)}\ \left( 9a - b^{2} \right)\left( b^{2} + 9a \right) = 81a² - b^{4}\]
\[\textbf{г)}\ \left( 0,7x + y^{2} \right)\left( 0,7x - y^{2} \right) = 0,49x² - y^{4}\]
\[\textbf{д)}\ \left( 10p^{2} - 0,3q^{2} \right)\left( 10p^{2} + 0,3q^{2} \right) = 100p^{4} - 0,09q^{4}\]
\[\textbf{е)}\ \left( a^{3} - b^{2} \right)\left( a^{3} + b^{2} \right) = a^{6} - b^{4}\]
\[\textbf{ж)}\ \left( c^{4} + d^{2} \right)\left( d^{2} - c^{4} \right) = d^{4} - c^{8}\]
\[\textbf{з)}\ \left( 5x^{2} + 2y^{3} \right)\left( 5x^{2} - 2y^{3} \right) = 25x^{4} - 4y^{6}\]
\[\textbf{и)}\ \left( 1,4c - 0,7y^{3} \right)\left( 0,7y^{3} + 1,4c \right) = 1,96c² - 0,49y^{6}\]
\[к)\ \left( 1,3a^{5} - 0,1b^{4} \right)\left( 1,3a^{5} + 0,1b^{4} \right) = 1,69a^{10} - 0,01b^{8}\ \]