併項

自己做
睇答案

a x + a y - b x - b y

= a ( ) - b ( )

= ( ) ()               
     
   a x  +  a y  -  b x  -  by
=          
=  

a x - a y - b x + b y

= a ( ) - b ( )

= ( ) ( )

     
   a x  -  a y  -  b x  +  by
=          
=  

x2 - 2c - 2x + cx

= x ( ) + c ( )

= ( ) ( )

 

x2 - 2c - 2x + cx
=          
=  

36h2k+12k-3hk2-144h

=3(12h2k+4k-hk2-48h)

=3[12h ( )-k( ) ]

= 3 ( ) ( )

 

36h2k+12k-3hk2-144h

=3(12h2k+4k-hk2-48h)

=        
=  

 

x2+ax-bx+xy-by-ab

= x ( ) -b ( )

= ( ) ( )

 

x2+ax-bx+xy-by-ab

=         
=