\[\boxed{\text{1171\ (1171).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ 6x^{2} + (2y - 3x)(2y + 3x) =\]
\[= 6x^{2} + 4y^{2} - 9x^{2} = 4y^{2} - 3x^{2}\]
\[2)\ (a + 2)(a - 3) - (4 - a)(a + 4) =\]
\[= a^{2} - 3a + 2a - 6 - 16 + a^{2} =\]
\[= 2a^{2} - a - 22\]
\[= 25 - 4x^{2} - 12 + 6x + 8x - 4x^{2} =\]
\[= - 8x^{2} + 14x + 13\]
\[= \left( 16a^{4}b^{4} - 1 \right)\left( 16a^{4}b^{4} + 1 \right) =\]
\[= 256a^{8}b^{8} - 1\ \]