a2-b2=(a-b)(a+b)
(8-x)*(8+x)=-
2
(a-8)*(a+8)=2-
(8-cd)*(8+cd)=-(
)2
(6b-8)*(6b+8)=*
2-
(6b-8)*(6b+8)=(*
)2-
(12-m)*(12+m)=-
2
(z-12)*(z+12)=2-
(12-cd)*(cd+12)=-(
)2
(8b-12)*(8b+12)=*
2-
(8b-12)*(12+8b)=(*
)2-
(6ab-zx)*(zx+6ab)=*(
)2-(
)2
(6z+a)*(a-6z)=2-
*
2
(mlu+6k)*(6k-mlu)=*
2-(
)2
(12bc3-6x)*(6x+12bc3)=*b2c6-
*
2
(12bc3-6x)*(6x+12bc3)=(*bc3)2-
*
2