Based on your description, it sounds like the graph has a vertical asymptote at \( x = 12 \). Vertical asymptotes occur where the function approaches infinity or negative infinity as the input approaches a certain value, and in this case, you've described the behavior of the curve as it approaches the line \( x = 12 \).
Thus, the equation representing the vertical asymptote of the graph is:
\( x = 12 \).