Прошуууу,помогитееее (m+n)(m-n)(m^2-n^2)+2m^2n^2 (x+2)^2×(x-2)^2-x^4+16
(m+n)^2+(m-n)^2/(m^2+n^2)= (m^2+2mn+n^2+m^2-2mn+n^2)/(m^2+n^2)= (2m^2+2n^2)/(m^2+n^2)=2