This is a problem from Terence Tao's book, and I cannot locate the solution anywhere, so I thought I'd post it here. 1. The problem statement, all variables and given/known data X^4+131=3y^4, Show that the equation has no solutions when x and y are integers. 2. Relevant equations None? Not sure. 3. The attempt at a solution I thought of using modular arithmetic, but I can't really work it correctly.