a2-b2=(a-b)(a+b)
(8-x)*(8+x)=-
2
(a-8)*(a+8)=2-
(8-cd)*(8+cd)=-(
)2
(2b-8)*(2b+8)=*
2-
(2b-8)*(2b+8)=(*
)2-
(14-m)*(14+m)=-
2
(z-14)*(z+14)=2-
(14-cd)*(cd+14)=-(
)2
(8b-14)*(8b+14)=*
2-
(8b-14)*(14+8b)=(*
)2-
(2ab-zx)*(zx+2ab)=*(
)2-(
)2
(2z+a)*(a-2z)=2-
*
2
(mlu+2k)*(2k-mlu)=*
2-(
)2
(14bc3-2x)*(2x+14bc3)=*b2c6-
*
2
(14bc3-2x)*(2x+14bc3)=(*bc3)2-
*
2