Source: Romania District Olympiad 2013,grade X(problem 1)
March 14, 2013
algebra proposedalgebra
Problem Statement
Let a,b∈R and z∈C\R so that ∣a−b∣=∣a+b−2z∣.
a) Prove that the equation ∣z−a∣x+∣zˉ−b∣x=∣a−b∣x, with the unknown number x∈R, has a unique solution.
b) Solve the following inequation ∣z−a∣x+∣zˉ−b∣x≤∣a−b∣x, with the unknown number x∈R.
The Mathematical Gazette