а) (х - 3) (х - 7) - 2х (3х - 5) = x^2 - 7x - 3x + 21 - 6x^2 + 10x = -5x^2 - x + 21
б) 4a(a - 2) - (a - 4)2 = 4a^2 - 8a - a^2 + 8a - 16 = 3a^2 - 16
в) 2(t + 1)^2 - 4t = 2(t^2 + 2t + 1) - 4t = 2t^2 + 4t + 2 - 4t = 2t^2 + 2
а) (х - 3) (х - 7) - 2х (3х - 5) = x^2 - 7x - 3x + 21 - 6x^2 + 10x = -5x^2 - x + 21
б) 4a(a - 2) - (a - 4)2 = 4a^2 - 8a - a^2 + 8a - 16 = 3a^2 - 16
в) 2(t + 1)^2 - 4t = 2(t^2 + 2t + 1) - 4t = 2t^2 + 4t + 2 - 4t = 2t^2 + 2