1. Need Help!!!

I have a problem that I can't solve.You can help me!
On the blackboard,the mathematics professor wrote a poly monial f(x) with interger coefficient and said,"Today is my son's birthday.When his age A is substitute for x,f(A)=A.You will note also that f(0)=P and that P is a prime number geater than A".How old is the professor's son?
Thank you so much!!!

2. Originally Posted by sodymong
I have a problem that I can't solve.You can help me!
On the blackboard,the mathematics professor wrote a poly monial f(x) with interger coefficient and said,"Today is my son's birthday.When his age A is substitute for x,f(A)=A.You will note also that f(0)=P and that P is a prime number geater than A".How old is the professor's son?
Well if the answer is unique it is $1$. That A=1 is a possible
$f(x)=x^2-Px+P$