【文档说明】《分式的基本性质应用:约分、通分》PPT课件3-八年级上册数学人教版.ppt,共(15)页,351.000 KB,由小喜鸽上传
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新课导入一、分式的基本性质1.填空:2(1),22xxxx2233;6xxyxyx2(2),ababab222abaab12xa(a+b)b(2a-b)(b≠0)•分式的约分、通分二、分式的约分例1.约分:22222225912
156961263.33abcxabcxxxxyyxy();();()222551=-153abcaabcb:()解22932=693xxxxx()22612632()33xxyyxyxy
()分式的通分:根据分式的基本性质,把几个异分母的分式分别化成与原来的分式相等的同分母的分式,叫做分式的通分.三、分式的通分通分的关键是找分母的最简公分母2222333222,bcbcababbcabc2222222222.ababaaababcabca
abc()运用新知例通分:2223112332.abxxyababcxy()与;()与()解:(1)最简公分母是222abc.2223112332.abxxyababcxy()与;()与
()运用新知例通分:解:(2)最简公分母是23.xy()2113333,xyxyxyxyxyxy()()()()2223333.xxxxyxyxy()()()2222
2212341bcxyyxxymmacxyxym()();();();().()解:221bcbaca();四、课堂练习练习:约分:22xyyxyxyxy()();22222212341bcxyyxxymmacxyxym()();();();()
.()四、课堂练习练习:约分:2223xxyxxyxxyxyxy()();()()22141111.---mmmmmmmmm()()()()解:四、课堂练习,xxcxcababc
abc.yyayabcbcabca解:(1)最简公分母是.abc1xyabbc()与;22324cacbdb()与;231413324xxxxx(),,.练习通分:四、课堂练习2224844,ccbbcbdbd
bbd222333444.acacdacdbbdbd解:(2)最简公分母是24.bd1xyabbc()与;22324cacbdb()与;231413324xxxxx(),,.练习通分:2231166122612,xxxxxxxxx
()()22234441633412,xxxxxx()()四、课堂练习解:(3)最简公分母是312.x1xyabbc()与;22324cacbdb()与;231413324xxxxx(),,.练习通分:3331133144312.xxxxxx
()()()()1.通过本节课的学习,你有哪些收获?2.通过这节课的学习,你觉得有哪些知识是难以把握的?你有何想法?课堂小结