Question

下列運(yùn)算正確的是（　　）                                                                     

A．5m+2m=7m²           B．﹣2m²m³=2m⁵                                            

C．（﹣a²b）³=﹣a⁶b³  D．（b+2a）（2a﹣b）=b²﹣4a²                           

Answer 1

C【考點(diǎn)】?jī)绲某朔脚c積的乘方；合并同類項(xiàng)；單項(xiàng)式乘單項(xiàng)式；平方差公式．                  

【分析】A、依據(jù)合并同類項(xiàng)法則計(jì)算即可；B、依據(jù)單項(xiàng)式乘單項(xiàng)式法則計(jì)算即可；C、依據(jù)積的乘方法則計(jì)算即可；D、依據(jù)平方差公式計(jì)算即可．                                                                     

【解答】解：A、5m+2m=（5+2）m=7m，故A錯(cuò)誤；                                   

B、﹣2m²m³=﹣2m⁵，故B錯(cuò)誤；                                                            

C、（﹣a²b）³=﹣a⁶b³，故C正確；                                                         

D、（b+2a）（2a﹣b）=（2a+b）（2a﹣b）=4a²﹣b²，故D錯(cuò)誤．                 

故選：C．                                                                                         

【點(diǎn)評(píng)】本題主要考查的是整式的計(jì)算，掌握合并同類項(xiàng)法則、單項(xiàng)式乘單項(xiàng)式法則、積的乘方法則以及平方差公式是解題的關(guān)鍵．