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

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

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

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

(6b-2)*(6b+2)=*2-

(6b-2)*(6b+2)=(*)2-

(1-m)*(1+m)=-2

(z-1)*(z+1)=2-

(1-cd)*(cd+1)=-()2

(2b-1)*(2b+1)=*2-

(2b-1)*(1+2b)=(*)2-

(6ab-zx)*(zx+6ab)=*()2-()2

(6z+a)*(a-6z)=2-*2

(mlu+6k)*(6k-mlu)=*2-()2

(1bc3-6x)*(6x+1bc3)=*b2c6-*2

(1bc3-6x)*(6x+1bc3)=(*bc3)2-*2



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