Question

Упростите выражение:
(3m^2+3n^2)-(2m+n)(m+2n)

Answer 1

(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