MathDB
2010 SMO

Source:

November 1, 2010
quadraticsalgebranumber theory unsolvednumber theory

Problem Statement

Let a,b,c{0,1,2,,9}a,b,c\in\{0,1,2,\cdots,9\}.The quadratic equation ax2+bx+c=0ax^2+bx+c=0 has a rational root. Prove that the three-digit number abcabc is not a prime number.