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

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

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

(8-cd)*(8+cd)=-()2

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

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

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

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

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

(8b-7)*(8b+7)=*2-

(8b-7)*(7+8b)=(*)2-

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

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

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

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

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



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