(a-b-c+d)(a-b+c-d)=[(a-b)- ( )][( )+(c-d)]填空题

问题描述:

(a-b-c+d)(a-b+c-d)=[(a-b)- ( )][( )+(c-d)]填空题

=[(a-b)- (c-d )][(a-b )+(c-d)]