MathDB
x^3 +? x^2 +? x +? = 0 , integer solutions game

Source: Dutch NMO 1997 p3

January 29, 2020
gameIntegerinteger solutionspolynomialwinning strategyalgebra

Problem Statement

a. View the second-degree quadratic equation x2+?x+?=0x^2+? x +? = 0 Two players successively put an integer each at the location of a question mark. Show that the second player can always ensure that the quadratic gets two integer solutions. Note: we say that the quadratic also has two integer solutions, even when they are equal (for example if they are both equal to 33).
b.View the third-degree equation x3+?x2+?x+?=0x^3 +? x^2 +? x +? = 0 Three players successively put an integer each at the location of a question mark. The equation appears to have three integer (possibly again the same) solutions. It is given that two players each put a 33 in the place of a question mark. What number did the third player put? Determine that number and the place where it is placed and prove that only one number is possible.