a(4 - y) - 6(4-y) = (4-y) (a-6)
3x + xy² - x²y - 3y = x(3 - xy) - y(3 - xy) = (3 - xy)(x - y)
2x² + 5x - 3 = 2x(x + 3) - (x + 3) = (x + 3)(2x - 1)
a(4 - y) - 6(4-y) = (4-y) (a-6)
3x + xy² - x²y - 3y = x(3 - xy) - y(3 - xy) = (3 - xy)(x - y)
2x² + 5x - 3 = 2x(x + 3) - (x + 3) = (x + 3)(2x - 1)