2m³ - 6m² - 2m
= 2m(m² - 3m - 1)
= 2m(m² - 3m + 3/4 - 7/4)
= 2m [(m - 3/2)² - 7/4]
= 2m (m - 3/2 +√7/2) (m - 3/2 -√7/2)