Question

Factorise :a - b - a3+ b3

Answer 1

we know that,
a3 - b3 = ( a - b )( a2 + ab + b2 ) ....(1)
a - b - a3+ b3
= a - b - ( a3 - b3 )
= ( a - b ) - ( a - b )[ a2 + ab + b2 ] [ From (1) ]
= ( a - b )[ 1 - a2 - ab - b2 ]