(a+b+c)(a+b- c)=[( )+( )][( )- ( )]
问题描述:
(a+b+c)(a+b- c)=[( )+( )][( )- ( )]
(a- b+c)(a+b- c)=[( )+( )][( )- ( )]
(a+b+c)(a- b- c)=[( )+( )][( )- ( )]
答
1.[ (a+b)+(C)][(a+b)-(c)]
2. [a+(b-c)][a-(b-c)]
3. [a+(b+c)][a-(b+c)]