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

(4-x)*(4+x)=-2

(a-4)*(a+4)=2-

(4-cd)*(4+cd)=-()2

(3b-4)*(3b+4)=*2-

(3b-4)*(3b+4)=(*)2-

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

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

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

(4b-2)*(4b+2)=*2-

(4b-2)*(2+4b)=(*)2-

(3ab-zx)*(zx+3ab)=*()2-()2

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

(mlu+3k)*(3k-mlu)=*2-()2

(2bc3-3x)*(3x+2bc3)=*b2c6-*2

(2bc3-3x)*(3x+2bc3)=(*bc3)2-*2



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