а) (3ab + 5a - b) - (12ab - 3a) = 3ab + 5a - b - 12ab + 3a = -9ab + 8a - b
б) 2x^2(3 - 5x^3) = 6x^2 - 10x^5
в) (2a - 3c)(a + 2c) = 2a^2 + 4ac - 3ac - 6c^2 = 2a^2 + ac - 6c^2
г) (y - 1)(y^2 + 2y - 4) = y^3 + 2y^2 - 4y - y^2 - 2y + 4 = y^3 + y^2 - 6y + 4
д) (3x^3 - 6x^2) / 3x^2 = x(3x - 6) / 3x = x(3(x - 2)) / 3x = x(x - 2)
а) (3ab + 5a - b) - (12ab - 3a) = 3ab + 5a - b - 12ab + 3a = -9ab + 8a - b
б) 2x^2(3 - 5x^3) = 6x^2 - 10x^5
в) (2a - 3c)(a + 2c) = 2a^2 + 4ac - 3ac - 6c^2 = 2a^2 + ac - 6c^2
г) (y - 1)(y^2 + 2y - 4) = y^3 + 2y^2 - 4y - y^2 - 2y + 4 = y^3 + y^2 - 6y + 4
д) (3x^3 - 6x^2) / 3x^2 = x(3x - 6) / 3x = x(3(x - 2)) / 3x = x(x - 2)