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

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

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

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

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

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

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

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

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

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

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

(4ab-zx)*(zx+4ab)=*()2-()2

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

(mlu+4k)*(4k-mlu)=*2-()2

(3bc3-4x)*(4x+3bc3)=*b2c6-*2

(3bc3-4x)*(4x+3bc3)=(*bc3)2-*2



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