x1+x2=2(p+1) x1*x2=p^2+8(x1-x2)^2=(x1+x2)^2-4*x1*x2 =[2(p+1)]^2-4*(p^2+8) =(4p^2+8p+4)-(4p^2+32) =8p-28|x1-x2|=(8p-28)^0.5=28p-28=4p=4
