Question

1)m(m^2-mn+n^2)-n(m^2+mn+n^2)

Answer 1

$m^3-m^2n+mn^2-m^2n-mn^2-n^3=m^3-2m^2n-n^3$

Answer 2

m (m² - mn + n²)- n (m² + mn +n²) = m³-m²n+n²m-m²n-n²m-n³ = m³-n³-2m²n

Answer 3

m(m²+mn+n²)-n(m²+mn+n²)= (m-n)(m²+mn+n²)= m³-n³