ab(a+b)(a−2b). (x+2)(x2−2x+4)(x−1). (a+y)(a2−ay+y2)(a−x). Exercise40. 6. 5x3. 6ax. 7ab2. 7. 2a2b2. x+3y. x+3. 2a+1. x+y. a+x. a+2b. x−1. x+3. x−6. x2−x+1. x−1. x−y. x−5. a−b−c. x+2y. x+4y.