To find out how much money Victor owes at the beginning of January, we need to evaluate the function \( f(x) \) at \( x = 0 \) (since January is the start of the time period).
The function given is:
\[ f(x) = -35x + 2500 \]
Substituting \( x = 0 \):
\[ f(0) = -35(0) + 2500 = 2500 \]
Therefore, Victor owes $2500 at the beginning of January.