a) 3x3+x2+ 3x + 1 = (3x3 + 3x) + (x2 + 1) = 3x(x2 + 1) + 1(x2 + 1) = (3x+1)(x2+1)
б) 2x + 2y - x2 - xy = 2(x+y) - x(x+y) = (2-x)(x+y)
Ответ: