Four solutions form an arithmetic progression
Source: Vietnam NMO 1985 Problem 5
February 12, 2009
parameterizationalgebra unsolvedalgebra
Problem Statement
Find all real values of parameter for which the equation in
16x^4 \minus{} ax^3 \plus{} (2a \plus{} 17)x^2 \minus{} ax \plus{} 16 \equal{} 0
has four solutions which form an arithmetic progression.