拆开,得
x^2-2x-mx+2m=p^2-2p-mp+2m
移项得x^2-p^2-2x+2p-mx+mp=0
(x-p)(x+p)-2(x-p)-m(x-p)=0
(x-p)(x+p-2-m)=0
x1=p,x2=m+2-p