выполните действие с многочленами: а) (-4mn - 2n^2+3m)+(n^2=3mn-4n) б) (-4mn - 2n^2+3m)-(n^2=3mn-4n) в) -2mn^2(n^2+3mn-4n)

(2m^2- n)(m+n) = 2m^3 - mn + 2mn^2 - n^2 (3n^2 -n - 2)(n^2 + 2n-5) = = 3n^4 - n^3 - 2n^2 + 6n^3 - 2n^2-4n - 15n^2 +5n+ 10 = = 3n^4 -5n^3 - 19n^2+n + 10 = (3m-4n)(m - 7n -2n) = (3m-4n)(m-9n) (m - 8n)(3m - 4n) -2n(3m - 4n) =