There are two curves with a vertical asymptote x=3. One curve passes (1,0), and another curve passes (4,0). Estimate the intervals on which the function is increasing or decreasing.

Please directly answer the question and provide the final value, e.g., 1, 2.5, 300.
Question: There are two curves with a vertical asymptote x=3. One curve passes (1,0), and another curve passes (4,0). Estimate the intervals on which the function is increasing or decreasing.

Please first conduct reasoning, and then answer the question and provide the final value, e.g., 1, 2.5, 300, at the end.
Question: There are two curves with a vertical asymptote x=3. One curve passes (1,0), and another curve passes (4,0). Estimate the intervals on which the function is increasing or decreasing.
