3) 3x^2 - 6x = x(3x - 6)
x(x - 3) - 8(x - 3) = (x - 3)(x - 8)
4) 3(x - 4) + x^2 - 4x = 3(x - 4) + x(x - 4) = (x - 4)(3 + x)
2x - 8 - x(x - 4) = 2(x - 4) - x(x - 4) = (x - 4)(2 - x)
x^3 + 5x^2 - 2x - 10 = x^2(x + 5) - 2(x + 5) = (x + 5)(x^2 - 2)
x^3 - 6x^2 - 2x + 12 = x^2(x - 6) - 2(x - 6) = (x - 6)(x^2 - 2)