# Not constant

Author: mathforces
Problem has been solved: 23 times

Русский язык | English Language

Some integers $x$, $y$, $z$ and $t$ satisfy the equality $x^2+2y^2+z^2+2t^2 = 2(xy+yz-zt+tx)$. Find the largest possible value for $\frac{x-y}{y-z}$ if it is known that $x \ge y \ge z \ge t$.