Problem #PRU-78244

Problems Algebra and arithmetic Absolute value Absolute value of a number (other) Number systems Decimal number system Algebraic equations and systems of equations Higher order equations. Palindromic polynomial equations Equations of higher order (other)

Problem

Two people play a game with the following rules: one of them guesses a set of integers (x1,x2,,xn) which are single-valued digits and can be either positive or negative. The second person is allowed to ask what is the sum a1x1++anxn, where (a1,,an) is any set. What is the smallest number of questions for which the guesser recognizes the intended set?