a2-b2=(a-b)(a+b)

(2-x)*(2+x)=-2

(a-2)*(a+2)=2-

(2-cd)*(2+cd)=-()2

(2b-2)*(2b+2)=*2-

(2b-2)*(2b+2)=(*)2-

(16-m)*(16+m)=-2

(z-16)*(z+16)=2-

(16-cd)*(cd+16)=-()2

(2b-16)*(2b+16)=*2-

(2b-16)*(16+2b)=(*)2-

(2ab-zx)*(zx+2ab)=*()2-()2

(2z+a)*(a-2z)=2-*2

(mlu+2k)*(2k-mlu)=*2-()2

(16bc3-2x)*(2x+16bc3)=*b2c6-*2

(16bc3-2x)*(2x+16bc3)=(*bc3)2-*2



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