1. The graph of the fractional-linear function $\frac{3 x-3}{x-2}$ was rotated around some point by some angle, resulting in the graph of the fractional-linear function $\frac{-x+a}{2 x-4}$. What can $a$ be? If there are multiple possible values, list them in any order separated by a semicolon.
Answer: $-4,8\|-4 ; 8\| 8 ;-4 \| 8,-4$