mп^4-cп^4\сп^3-mп^3= (mn-cn)(mn+cn)(mn2+cn2) / (cn-mn)(cn2+cmn2+mn2)=
(mn-cn)(mn2+cn2) / -(cn2+cmn2+mn2)
mп^4-cп^4\сп^3-mп^3= (mn-cn)(mn+cn)(mn2+cn2) / (cn-mn)(cn2+cmn2+mn2)=
(mn-cn)(mn2+cn2) / -(cn2+cmn2+mn2)