Question

(m+n)的三次方-(m-n)的二次方（n+m)

Answer 1

(m+n)的三次方-(m-n)的二次方（n+m)

=(m+n)[(m+n)^2-(m-n)^2]

=(m+n)(m+n+m-n)(m+n-m+n)

=4mn(m+n).