MathDB
x^2 + ax + b with a,b integers, add 1 or - 1 to a or b (HOMC 2019 JI-12)

Source:

November 7, 2020
polynomialalgebracombinatoricsIntegers

Problem Statement

Given an expression x2+ax+bx^2 + ax + b where a,ba,b are integer coefficients. At any step, one can change the expression by adding either 11 or 1-1 to only one of the two coefficients a,ba, b. a) Suppose that the initial expression has a=7a =-7 and b=19b = 19. Show your modification steps to obtain a new expression that has zero value at some integer value of xx. b) Starting from the initial expression as above, one gets the expression x217x+9x^2 - 17x + 9 after mm modification steps. Prove that at a certain step kk with k<mk < m, the obtained expression has zero value at some integer value of xx.