a³
−
b³
Difference of Cubes · Interactive Explorer
📐
Formula
Full derivation and simplified identity for a³ − b³
🧮
Solve
Step-by-step guided questions to factor expressions
← Home
Deriving
a³ − b³
Step-by-step derivation
start
(a − b)³ = a³ − b³ − 3ab(a − b)
or,
(a − b)³ + 3ab(a − b) = a³ − b³
or,
(a − b)(a − b)² + 3ab(a − b) = a³ − b³
or,
(a − b){(a − b)² + 3ab} = a³ − b³
∵ (a − b) is common on both
or,
(a − b)(a² − 2ab + b² + 3ab) = a³ − b³
∵ using formula of (a − b)²
or,
(a − b)(a² + ab + b²) = a³ − b³
Simplified identities
(i)
a³ − b³
= (a − b)³ + 3ab(a − b)
(ii)
a³ − b³
= (a − b)(a² + ab + b²)
← Home
8x³ − y³