The quadratic trinomials f, g and h are such that for every real x the numbers f(x), g(x) and h(x) are the lengths of the sides of some triangles, and the numbers f(x)−1, g(x)−1 and h(x)−1 are not the lengths of the sides of the triangle. Prove that at least of the polynomials f+g−h, f+h−g, g+h−f is constant. algebraquadratic trinomialtrinomialquadraticsconstantSides of a triangle