a) 7a - 7b + an - bn = 7(a - b) + n(a - b) = (a - b)(7 + n)б) ax + ay - x - y = a(x + y) - (x + y) = (a - 1)(x + y)
a) 7a - 7b + an - bn = 7(a - b) + n(a - b) = (a - b)(7 + n)
б) ax + ay - x - y = a(x + y) - (x + y) = (a - 1)(x + y)