What is a rational zero?

1 Answer
Dec 28, 2015

A rational zero of a polynomial f(x) in a variable x is a fraction p/q such that f(p/q) = 0 where p and q are integers.

Explanation:

A rational number is a number that can be expressed in the form p/q for some integers p and q.

A zero of an expression f(x) is a value of x such that f(x) = 0.

So a rational zero of an expression f(x) is basically a fraction p/q such that f(p/q) = 0.

For example, 2x^2-3x-5 has rational zeros x=-1 and x=5/2, since substituting either of these values for x in the expression results in the value 0.