709. Разложите на множители многочлен: a) mx + my + 6x + 6y; б) 9x + ay + 9y + ax; в) 7a - 7b + an – bn; г) ах+ау-х-у; д) 1-bx-x + b; е) xy + 2y - 2x - 4.

a) mx + my + 6x + 6y = m(x + y) + 6(x + y) = (m + 6)(x + y) б) 9x + ay + 9y + ax = 9x + 9y + ay + ax = 9(x + y) + a(y + x) = (9 + a)(x + y) в) 7a - 7b + an - bn = 7(a - b) + n(a - b) = (7 + n)(a - b) г) ax + ay - x - y = a(x + y) - (x + y) = (a - 1)(x + y) д) 1 - bx - x + b = 1 + b - bx - x = (1 + b) - x(b + 1) = (1 - x)(1 + b) е) xy + 2y - 2x - 4 = y(x + 2) - 2(x + 2) = (y - 2)(x + 2)