a³ ± b³ = (a ± b) (a² ∓ ab + b²)
1) a=8x ; b=y
512x³ - y³ = (8x - y) (64x² + 8xy + y²)
2) a=4m ; b=9
64m³ + 729 = (4m + 9) (16m² - 36m + 81)
3) a=10n ; b=5m
1000n³ - 125m³ = (10n - 5m) (100n² + 50mn + 25m²)
We may still factor out 5 from (10n - 5m) and 25 from (100n² + 50mn + 25m²), so
5 (2n - m) · 25 (4n² + 4mn + m²) = 125 (2n - m) (4n² + 4mn + m²)
