(a−5b)(a−5b). (c−3d)(c−3d). (2x−1)(2x−1). (2a−3b)(2a−3b). (3a−4b)(3a−4b). (x+4y)(x+4y). (x−4y)(x−4y). (2x−5y)(2x−5y). (1+10a)(1+10a). (7a−2)(7a−2). (6a+5b)(6a+5b). (9x−2b)(9x−2b). (mn+7x2)(mn+7x2). Exercise38. (a+2)(a+3). (a−2)(a−3). (a+1)(a+5). (a−1)(a−5). (a−1)(a+5). (a+1)(a−5). (c−3)(c−6). (c+3)(c+6). (c−3)(c+6). (c+3)(c−6). (x+2)(x+7). (x−2)(x−7).