4a2b(a+b)(a+b)(a−b). (y+2)(y+3)(y+4). (x+1)(x−1)(x2+1). (1+x)(1−x)(1+x+x2). (x+y)(x+y)(x−y)(x−y). x(x−3)(x+5)(x2+3x+9). (a+b+c)(a+b+c)(a+b−c). (x−a)(x−b)(x−c). a(a+b+c)(a+b−c). [4]Exercise42. 13b. 4m5n. 3m4p2. x22yz. a3b33c2. 2xy3. 2m3p. 3b2c4a3. 2y2z43. bc. 2a−3b2a. 3aa+2.