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

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

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

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

(8b-1)*(8b+1)=*2-

(8b-1)*(8b+1)=(*)2-

(7-m)*(7+m)=-2

(z-7)*(z+7)=2-

(7-cd)*(cd+7)=-()2

(1b-7)*(1b+7)=*2-

(1b-7)*(7+1b)=(*)2-

(8ab-zx)*(zx+8ab)=*()2-()2

(8z+a)*(a-8z)=2-*2

(mlu+8k)*(8k-mlu)=*2-()2

(7bc3-8x)*(8x+7bc3)=*b2c6-*2

(7bc3-8x)*(8x+7bc3)=(*bc3)2-*2


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