how to factorize?

1340u^3+1372(m^3-u^3)
= 1340u^3+1372m^3-1372u^2
= -32u^3+1372m^3
= 4 ( 343m^3 - 8u^3 )
= 4 [ ( 7m )^3 - ( 2u )^3 ]
= 4 ( 7m - 2u )( 49m^2 + 14mu + 4u^2 )

2008-02-11 23:13:53 補充：
Sor, 第二行係:1340u^3+1372m^3-1372u^3

2008-02-11 23:14:58 補充：
Formula used: a^3 - b^3 = ( a - b )( a^2 + ab + b^2 )

1340u^3+1372(m^3-u^3)=?