# Prove that $6 - \sqrt{2}$ is Irrational by contradiction

What is a Proof by Contradiction, and how to prove by contradiction that $6 - \sqrt{2}$ is an irrational number?

• Suppose that $6-\sqrt 2$ is rational. Then... – abiessu Mar 23 '15 at 17:56
• then what should I do... – Hussain Halai Mar 23 '15 at 18:00