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

(5-x)*(5+x)=-2

(a-5)*(a+5)=2-

(5-cd)*(5+cd)=-()2

(7b-5)*(7b+5)=*2-

(7b-5)*(7b+5)=(*)2-

(16-m)*(16+m)=-2

(z-16)*(z+16)=2-

(16-cd)*(cd+16)=-()2

(5b-16)*(5b+16)=*2-

(5b-16)*(16+5b)=(*)2-

(7ab-zx)*(zx+7ab)=*()2-()2

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

(mlu+7k)*(7k-mlu)=*2-()2

(16bc3-7x)*(7x+16bc3)=*b2c6-*2

(16bc3-7x)*(7x+16bc3)=(*bc3)2-*2


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