Mx² - mz²= m(x²-z²)= m(x-z)(x+z)
5a²-10ab +5b² = 5(a² -2ab +b²) = 5(a-b)² = 5(a-b)(a-b)
45m +6n - 3mn - 90 = 3(15m + 2n - mn - 30) =
= 3( (15m - 30) + ( - mn + 2n)) = 3 ( 15(m - 2) - n(m - 2) ) =
= 3 (m - 2)(15 - n)
x² - y² - x + y = (x² - y²) +(-x + y) = (x-y)(x+y) - 1(x-y) =
= (x - y)(x + y - 1)
mk⁴ - k⁴ + mk³ - k³ = k³ (mk - k + m - 1) =
= k³ ( k(m - 1) + 1(m - 1) ) =
= k³ (k + 1)(m - 1)