Answer: m³ - 3m²n + 3mn² - n³ or
m³ -n³ -3m²n + 3mn² because mathematicians like their powers to be in order
Explanation:
Start with (m-n)(m-n) = m² -2mn + n² Then multiply (distribute)
(m-n)(m² -2mn + n²) to get
m³ -2m²n + mn² -m²n + 2mn² - n³
Combine like terms -2m²n -m²n = -3m²n and mn² + 2mn² = +3mn²
"bring down" m³ and -n³ and you have
m³ - 3m²n + 3mn² - n³