x³y² - xy - x³ + x = (x³y² - x³) - (xy - x) = x³(y² - 1) - x(y - 1) =
= x³(y - 1)(y + 1) - x(y - 1) = (y - 1)(x³y + x³ - x) = x(y - 1)(x²y + x² - 1)
