题目下列等式变形,错误的是( )A.若a=ba=ba=b,则a+2=b+2a+2=b+2a+2=b+2B.若a=ba=ba=b,则2a=2b2a=2b2a=2bC.若x+1=y+1x+1=y+1x+1=y+1,则x=yx=yx=yD.若a2=aa^{2}=aa2=a,则a=1a=1a=1知识点:不等式的性质章节:方程与不等式 / 不等式与不等式组