怎么解(a-1)^2=a²-2a+1
问题描述：
怎么解(a-1)^2=a²-2a+1
答
怎么解(a-1)^2=a²-2a+1
即
原式=(a-1)×(a-1)
=a (a-1)-(a-1)
=a^2-a-a+1
=a^2-2a+1