八年級(jí)數(shù)學(xué)上冊(cè)整式的乘法14.1.4整式的乘法第3課時(shí)整式的除法課件.pptx

1、學(xué)前溫故,新課早知,1.同底數(shù)冪相除,底數(shù)不變,指數(shù).用式子表示為:aman=(a0,m,n都是正整數(shù),并且mn). 2.任何不等于0的數(shù)的0次冪都等于,即a0=1(a0).,相減,am-n,1,學(xué)前溫故,新課早知,1.單項(xiàng)式相除,把系數(shù)與同底數(shù)冪分別相除作為;對(duì)于只在被除式里含有的字母,則連同它的指數(shù)作為. 2.計(jì)算2x3x2的結(jié)果是(). A.xB.2xC.2x5D.2x6 3.多項(xiàng)式除以單項(xiàng)式,先把這個(gè)多項(xiàng)式的每一項(xiàng)除以,再把所得的商. 4.(x2+xy)x=.,商的因式,商的一個(gè)因式,B,這個(gè)單項(xiàng)式,相加,x+y,1.單項(xiàng)式除以單項(xiàng)式 【例1】 計(jì)算:(1)24a3b23ab2; (2

2、)-9a3b4c2(-5a2bc)15a2b. 分析(1)直接利用單項(xiàng)式除以單項(xiàng)式法則計(jì)算即可;(2)應(yīng)先算單項(xiàng)式的乘法,再算單項(xiàng)式的除法. 解:(1)原式=(243)a3-1b2-2=8a2. (2)原式=(-9)(-5)a5b5c315a2b =45a5b5c315a2b=3a3b4c3.,2.多項(xiàng)式除以單項(xiàng)式 【例2】 計(jì)算: (1)(8m3n2-2m2+7m)(-2m); (2)(6x3y4z-4x2y3z+2xy3)2xy3. 解:(1)(8m3n2-2m2+7m)(-2m) =8m3n2(-2m)-2m2(-2m)+7m(-2m) (2)原式=6x3y4z2xy3-4x2y3z2x

3、y3+2xy32xy3=3x2yz-2xz+1.,1,2,3,4,5,6,1.下列運(yùn)算正確的是(). A.(6x6)(3x3)=2x2B.(8x8)(4x2)=2x6 C.(3xy)2(3x)=yD.(x2y2)(xy)2=xy,答案,1,2,3,4,5,6,答案,2.計(jì)算(6x3y-3xy2)3xy的結(jié)果是(). A.6x2-yB.2x2-y C.2x2+yD.2x2-xy,1,2,3,4,5,6,3.若規(guī)定a*b=ab-b,則 (6x5-15x4+3x3-4x2)*3x2的結(jié)果是.,答案,1,2,3,4,5,6,4.按程序x平方+xx進(jìn)行計(jì)算后,結(jié)果用x的式子表示是.(填入運(yùn)算結(jié)果的最簡(jiǎn)形式),答案,1,2,3,4,5,6,5.計(jì)算: (1)(2a)3(b3)24a3b4; (2)(4a3m+1b)(-8a2m+1); (3)(21x4y3+35x3y2+7x2y2)7x2y; (4)(-8x4y+12x3y2-4x2y3)4x2y.,答案,1,2,3,4,5,