(5m-2)(m-3)-(3m-1)(m-4)的结果是2m的2次方,可是是怎么得出来的呀?

问题描述:

(5m-2)(m-3)-(3m-1)(m-4)的结果是2m的2次方,可是是怎么得出来的呀?

=5m^2-17m+6-3m^2+13m-4
=2m^2-4m+2
=2(m^2-2m+1)
=2(m-1)^2