(4x-6)-(3x-9)×(5+2x) = (4x-6)-(15x + 6x^2 - 45 - 18x) = 4x - 6 - (-3x + 6x^2 - 45) = 4x - 6 + 3x - 6x^2 + 45 = 7x + 39 - 6x^2 = -6x^2 + 7x + 39