整式除法北师大版七年级下版.ppt

北师大版七年级数学下册 第一章整式的运算 第九节整式的除法 Evaluation only. ch Asposeslides for NET 4o dient P Evaluation only. Created with Aspose Slides for NET 4.0 dient Profilo 71 Copyright 2004-2017Aspose Pty L 知识回顾 1.同底数幂的除法 a÷a=a(a≠0,m,n都是正整数且mm) 2单项式与单项式相除的法则 单项式相除,把系数,同底数幂分别相除 后,作为商的因式;对于只在被除式里含有的 字母,则连同它的指数一起作为商的因式。 Evaluation only. ch Asposeslides for NET 4o dient P Evaluation only. Created with Aspose Slides for NET 4.0 dient Profilo 71 Copyright 2004-2017Aspose Pty L 你知道需要多少杯子吗? 图(1)的瓶子中盛满 了水,如果将这个瓶 子中的水全部倒入图 8 (2)的杯子中,那么 共需要多少个这样 的杯子?(单位:cm) (2)杯子 (1)瓶子 Evaluation only. ch Asposeslides for NET 4o dient P Evaluation only. Created with Aspose Slides for NET 4.0 dient Profilo 71 Copyright 2004-2017Aspose Pty L 探究新知 计算下列各题,说说你的理由 ①(ad+bd÷d= (2)(a2b+3b)÷a= (3)(xy2-2xy)÷(xy)= Evaluation only. ch Asposeslides for NET 4o dient P Evaluation only. Created with Aspose Slides for NET 4.0 dient Profilo 71 Copyright 2004-2017Aspose Pty L 探究方法小 方法1:利用乘除法的互逆 (1)∵(a+b)·d=ad+bd ∴,(ad+bd)÷d=a+b (2)∵:(ab+3b)·a=a2b+3ab ∴(a2b+3mb)÷a=mb+3b (3)∵(y2-2)·x=x3-2xy ∴(x3-2x)÷(x)=y2-2 Evaluation only. ch Asposeslides for NET 4o dient P Evaluation only. Created with Aspose Slides for NET 4.0 dient Profilo 71 Copyright 2004-2017Aspose Pty L 探究方法小到 方法2:类比有理数的除法 由有理数的除法 类比得到 a Cad+bd)id=(ad+bd).=a+b 1 (2)(a2b+3b+a=(ab+3b,1=ab+v (3)(xy2-2xy+(xy)=(xy2-2xy.1=y2-2 ey Evaluation only. ch Asposeslides for NET 4o dient P Evaluation only. Created with Aspose Slides for NET 4.0 dient Profilo 71 Copyright 2004-2017Aspose Pty L 知识要点 多项式除以单项式的法则 多项式除以单项式,先把这个多项式的每 一项分别除以单项式,再把所得的商相加。 Evaluation only. ch Asposeslides for NET 4o dient P Evaluation only. Created with Aspose Slides for NET 4.0 dient Profilo 71 Copyright 2004-2017Aspose Pty L 试一试 例3计算 (1)(6b+8b)÷(2b) (2)(27a3-1502+60)÷(3a) (3)(9x2y-6xy2)÷(3xy) (4)(3x2y-xy2+xy)÷(-xy) 2 2 Evaluation only. ch Asposeslides for NET 4o dient P Evaluation only. Created with Aspose Slides for NET 4.0 dient Profilo 71 Copyright 2004-2017Aspose Pty L 解:B习 =3a+4 分了 925+2 Evaluation o