(x-2x)(2-3x) = (x-2x)2 - (x-2x)3x = -x2 - (-2x)3x = -2x + 6x^2
(x^2-4)(x-3) = (x^2-4)x - (x^2-4)3 = x^3 - 4x - 3x^2 + 12 = x^3 - 3x^2 - 4x + 12
(a-v)(3a+4v-3) = (a-v)3a + (a-v)4v - (a-v)*3 = 3a^2 - 3av + 4av - 4v^2 - 3 = 3a^2 + av - 4v^2 - 3
(x-2x)(2-3x) = (x-2x)2 - (x-2x)3x = -x2 - (-2x)3x = -2x + 6x^2
(x^2-4)(x-3) = (x^2-4)x - (x^2-4)3 = x^3 - 4x - 3x^2 + 12 = x^3 - 3x^2 - 4x + 12
(a-v)(3a+4v-3) = (a-v)3a + (a-v)4v - (a-v)*3 = 3a^2 - 3av + 4av - 4v^2 - 3 = 3a^2 + av - 4v^2 - 3