(1)給定滿足多項式函數P(x)使得xP(x-1)=(x-10)P(x) for all x
(2)P(x)為實系數多項式，試證：若P(x)P(x+1)=P(x^2+x+1)則P(x)= - P(x)

(1) P(0)=P(9)=0 => 令P(x)=x(x-9)Q(x) 代入原式得Q(1)=Q(8)=0......
    P(x)=ax(x-1)(x-2).....*(x-9)