What are the possible integral zeros of P(p)=p^4-2p^3-8p^2+3p-4P(p)=p42p38p2+3p4?

1 Answer
Jan 14, 2017

The "possible" integral zeros are: +-1, +-2, +-4±1,±2,±4

Actually P(p)P(p) has no rational zeros.

Explanation:

Given:

P(p) = p^4-2p^3-8p^2+3p-4P(p)=p42p38p2+3p4

By the rational roots theorem, any rational zeros of P(p)P(p) are expressible in the form p/qpq for integers p, qp,q with pp a divisor of the constant term -44 and qq a divisor of the coefficient 11 of the leading term.

That means that the only possible rational zeros (which also happen to be integers) are:

+-1, +-2, +-4±1,±2,±4

In practice we find that none of these are actually zeros, so P(p)P(p) has no rational zeros.