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

(9-x)*(9+x)=-2

(a-9)*(a+9)=2-

(9-cd)*(9+cd)=-()2

(1b-9)*(1b+9)=*2-

(1b-9)*(1b+9)=(*)2-

(14-m)*(14+m)=-2

(z-14)*(z+14)=2-

(14-cd)*(cd+14)=-()2

(9b-14)*(9b+14)=*2-

(9b-14)*(14+9b)=(*)2-

(1ab-zx)*(zx+1ab)=*()2-()2

(1z+a)*(a-1z)=2-*2

(mlu+1k)*(1k-mlu)=*2-()2

(14bc3-1x)*(1x+14bc3)=*b2c6-*2

(14bc3-1x)*(1x+14bc3)=(*bc3)2-*2



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