a2-b2=(a-b)(a+b)
(6-x)*(6+x)=-
2
(a-6)*(a+6)=2-
(6-cd)*(6+cd)=-(
)2
(8b-6)*(8b+6)=*
2-
(8b-6)*(8b+6)=(*
)2-
(17-m)*(17+m)=-
2
(z-17)*(z+17)=2-
(17-cd)*(cd+17)=-(
)2
(6b-17)*(6b+17)=*
2-
(6b-17)*(17+6b)=(*
)2-
(8ab-zx)*(zx+8ab)=*(
)2-(
)2
(8z+a)*(a-8z)=2-
*
2
(mlu+8k)*(8k-mlu)=*
2-(
)2
(17bc3-8x)*(8x+17bc3)=*b2c6-
*
2
(17bc3-8x)*(8x+17bc3)=(*bc3)2-
*
2