## Task B-2.2.

Let $z=x+2i$ and $u=3+yi$ where $(x, y \in \mathbb{R})$ be complex numbers. Determine all ordered pairs of real numbers $(x, y)$ for which the real part of the number $\frac{z+u}{z-u}$ is zero, and the point $s$ with coordinates $(x, y)$ is 3 units away from the origin.