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

(3-x)*(3+x)=-2

(a-3)*(a+3)=2-

(3-cd)*(3+cd)=-()2

(6b-3)*(6b+3)=*2-

(6b-3)*(6b+3)=(*)2-

(13-m)*(13+m)=-2

(z-13)*(z+13)=2-

(13-cd)*(cd+13)=-()2

(3b-13)*(3b+13)=*2-

(3b-13)*(13+3b)=(*)2-

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

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

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

(13bc3-6x)*(6x+13bc3)=*b2c6-*2

(13bc3-6x)*(6x+13bc3)=(*bc3)2-*2



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