Question

решите пожалуйста очень надо

Answer 1

$1.)(2x - 3y)(2x + 3y) = 4x {}^{2} + 6xy - 6xy - 9y {}^{2} = 4x {}^{2} - 9y {}^{2} \\ (0.3a - 3y)(0.3a + 3y) = 0.09a {}^{2} + 0.9ay - 0.9ay - 9y \\ ( {?} {}^{2} = 0.09a {}^{2} - 9y {}^{2} \\ ( \frac{1}{3} p - \frac{1}{6} c)( \frac{1}{3} p + \frac{1}{6} c) = \frac{1}{9} p {}^{2} - \frac{1}{36} c {}^{2} \\ (ab - 5)(ab + 5) = a {}^{2} b {}^{2} + 5ab - 5ab - 25 = a {}^{2} b {}^{2} - 25 \\ (x {}^{2} - y {}^{2} )(x {}^{2} + y {}^{2} ) = x {}^{4} - y {}^{4} \\ 2.)(c + 2)(c - 2) - 4c(c - 1) = c {}^{2} - 4 - 4c {}^{2} + 4c = - 3c {}^{2} - 4 + 4c \\ (4a - 1)(4a + 1) + ( 9 + a)(a - 9) = 16a {}^{2} - 1 + a {}^{2} - 81 = 17a {}^{2} - 82 \\ (5x - 7y)5x + 7y) + (7x - 5y)(7x + 5y) = 25x {}^{2} - 49y {}^{2} + 49x {}^{2} - 25y {}^{2} = 74x {}^{2} - 74y {}^{2} = 74(x {}^{2} - y {}^{2} ) \\ (m - 1)(6 - m) - (10 - m)(m + 10) = 6m - m {}^{2} - 6 + m - (10m - m {}^{2} + 100 - 10m) = 7m - m {}^{2} - 6 - 100 + m {}^{2} = 7m - 106$