сократите дробь
4n^2-4nm+m^2
----------------------
4n^2-m^2
4n^2-4nm+m^2= (2n-m)^2 4n^2-m^2=(2n-m)(2n+m) ((2n-m)^2)/( (2n-m)(2n+m) )= (2n-m)/ (2n+m)