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

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

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

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

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

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

(18-m)*(18+m)=-2

(z-18)*(z+18)=2-

(18-cd)*(cd+18)=-()2

(6b-18)*(6b+18)=*2-

(6b-18)*(18+6b)=(*)2-

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

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

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

(18bc3-6x)*(6x+18bc3)=*b2c6-*2

(18bc3-6x)*(6x+18bc3)=(*bc3)2-*2


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