Question 12
(BUL) Find digits $x,y,z$ such that the equality $$\sqrt{\underbrace{\overline{xx\cdots x}}_{2n}-\underbrace{\overline{yy\cdots y}}_n}=\underbrace{\overline{zz\cdots z}}_n$$ holds for at least two values of $n\in\mathbb N$, and in that case find all $n$ for which this equality is true.