-1/3ab-1/4a平方+1/3a平方-(-2/3ab) =

问题描述:

-1/3ab-1/4a平方+1/3a平方-(-2/3ab) =

-1/3ab-1/4a平方+1/3a平方-(-2/3ab)
=-1/3ab-1/4a平方+1/3a平方+2/3ab
==-1/3ab+2/3ab—1/4a平方+1/3a平方
=ab+1/12a²