问题 选择题

下列运算正确的是························ (▲  )

 

A.a+a=2a2

B.a2·a=2a2

C.(-ab)2=2ab2

D.(2a)2 ÷a=4a

答案

答案:D

A.a+a=2a  B.a2·a=a3    C.(-ab)2=a2b2    D.(2a)2 ÷a=4a2÷a=4ª

故选D

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