You do not need to rely on a shady scan. Here are the legitimate, verified ways to access this book in digital format.
Some universities or math departments upload sample chapters (not the full book) with permission. These are "verified" in content but do not provide the complete textbook.
Lee Peng Yee's book has gone through multiple editions. A verified PDF will clearly state the edition (e.g., "Revised Edition 2010" or "First Edition 1995"). An unverified file might mix chapters from different editions, leading to disjointed learning.
If a direct PDF of "Pure Mathematics" by Lee Peng Yee is not readily available, consider: