а) 3a + 6 + ab + 2b = a(3 + b) + 2(3 + b) = (a + 2)(3 + b)
б) 20fk - 12fn - 25km + 15mn = 4f(5k - 3n) - 5m(5k - 3n) = (4f - 5m)(5k - 3n)
в) ab + ac + af + b + c + f = a(b + c + f) + (b + c + f) = (a + 1)(b + c + f)
а) 3a + 6 + ab + 2b = a(3 + b) + 2(3 + b) = (a + 2)(3 + b)
б) 20fk - 12fn - 25km + 15mn = 4f(5k - 3n) - 5m(5k - 3n) = (4f - 5m)(5k - 3n)
в) ab + ac + af + b + c + f = a(b + c + f) + (b + c + f) = (a + 1)(b + c + f)