(a-5)(11-b) = 11a - ab - 55 + 5b;(-8-a)(b+2) = -8b - 2 - ab - 2a;(-7-b)(a-7) = -7a + 49 + 7b - b;(x-4)(x+8) = x^2 + 8x - 4x - 32 = x^2 + 4x - 32;(x-5)(9-x) = 9x - x^2 - 45 + 5x = -x^2 + 14x - 45;(8+3x)(2y-1) = 16y - 8 + 6xy - 3x;(2a-1)(3a+7) = 6a + 14 - 3a - 7 = 3a + 7;(3a-2b)(2a-3b) = 6a - 9b - 4ab + 6b^2;(15a+27)(-5a-9) = -75a^2 - 135a - 135a - 243 = -75a^2 - 270a - 243.
(a-5)(11-b) = 11a - ab - 55 + 5b;
(-8-a)(b+2) = -8b - 2 - ab - 2a;
(-7-b)(a-7) = -7a + 49 + 7b - b;
(x-4)(x+8) = x^2 + 8x - 4x - 32 = x^2 + 4x - 32;
(x-5)(9-x) = 9x - x^2 - 45 + 5x = -x^2 + 14x - 45;
(8+3x)(2y-1) = 16y - 8 + 6xy - 3x;
(2a-1)(3a+7) = 6a + 14 - 3a - 7 = 3a + 7;
(3a-2b)(2a-3b) = 6a - 9b - 4ab + 6b^2;
(15a+27)(-5a-9) = -75a^2 - 135a - 135a - 243 = -75a^2 - 270a - 243.