(m + n)^3 : (m + n) + mn - m^2

Question

(m + n)^3 : (m + n) + mn - m^2

Answer 1

=(m+n)^2+mn-m^2=(m+n+m)(m+n-m)+mn=(2m+n)n+mn=2mn+n^2+mn=3mn+n^2=n(3m+n)