Skip to main content
OlympiadHQ

Browse · MATH

Print

jmc

algebra intermediate

Problem

A polynomial of degree four with leading coefficient 1 and integer coefficients has two real zeros, both of which are integers. Which of the following can also be a zero of the polynomial?

(A)

(B)

(C)

(D)

(E)
Solution
If and are the integer zeros, the polynomial can be written in the form The coefficient of , , is an integer, so is an integer. The coefficient of , , is an integer, so is also an integer. Applying the quadratic formula gives the remaining zeros as Answer choices (A), (B), (C), and (E) require that , which implies that the imaginary parts of the remaining zeros have the form . This is true only for choice . Note that choice (D) is not possible since this choice requires , which produces an imaginary part of the form , which cannot be .
Final answer
\text{(A)}