a2-b2=(a-b)(a+b)
(8-x)*(8+x)=-
2
(a-8)*(a+8)=2-
(8-cd)*(8+cd)=-(
)2
(3b-8)*(3b+8)=*
2-
(3b-8)*(3b+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-
(3ab-zx)*(zx+3ab)=*(
)2-(
)2
(3z+a)*(a-3z)=2-
*
2
(mlu+3k)*(3k-mlu)=*
2-(
)2
(12bc3-3x)*(3x+12bc3)=*b2c6-
*
2
(12bc3-3x)*(3x+12bc3)=(*bc3)2-
*
2