m^2-4mn+4n^2/m^2-4n^2=

问题描述:

m^2-4mn+4n^2/m^2-4n^2=

m^2-4mn+4n^2/m^2-4n^2
=(m-2n)²/(m+2n)(m-2n)
=(m-2n)/(m+2n)