СРОЧНО,,,,,,,,...........
m(m+n)–4mn+n(m+n) m(m–n)+n(m (-------------------------------):(------------------- m+n (m–n)(m+n) +n)–2mn m^2+mn–4mn+mn+n^2 -------------) = ---------------------------------- : m+n m^2–mn+mn+n^2–2mn : ----------------------------------- = (m–n)(m+n) m^2–2mn+n^2 m^2–2mn+n^2 = ---------------------- : ---------------------- = m+n (m–n)(m+n) (m–n)^2•(m–n)(m+n) = ------------------------------ = m–n (m+n)•(m–n)^2