PPT课程 主讲老师:第11课乘法公式复习课22-ab22+2+aab b22-2+aabb2ab+2ab解：a2b2(ab)22ab 3222 5a-b-cb+cb+cbcbcy1y1解：原式(xy)1(xy)1 (xy)212 x22xyy21解：原式(xy)3(xy)3 (xy)232 x22xyy29解：原式(xy)12 (xy)22(xy)112 x22xyy22x2y1解：原式x(y1)x(y1)x2(y1)2 x2(y22y1)x2y22y1解：原式x(y3)x(y3)x2(y3)2 x2(y26y9)x2y26y9BC解：依题意：5(a4)2542 5(a28a16)516 5(a28a1616)5(a28a)5a240a (cm3)解：(1)S和S大正方形S小正方形 a2b2 (ab)22ab 10222060谢谢！
