$\frac{10i + 2}{2i} = \frac{10i}{2i} + \frac{2}{2i} = 5 + \frac{1}{i}$

Multiply $\frac{1}{i}$ by $\frac{i}{i}$:

$\frac{1}{i} \cdot \frac{i}{i} = \frac{i}{i^2} = \frac{i}{-1} = -i$

$= 5 - i$