fix(curriculum): update textbook links and add download instructions for Algebra and Trigonometry (freeCodeCamp#57622)

Co-authored-by: Naomi <[email protected]>

Author: Sembauke

curriculum/challenges/english/17-college-algebra-with-python/learn-applications-of-linear-systems/word-problems.md

@@ -14,7 +14,9 @@ This first video will look at key words that tell you what math operation to use
 
 \- <a href="https://lyryx.com/subjects/business/business-mathematics/" target="_blank" rel="noopener noreferrer nofollow">Business Math, a Step-by-Step Handbook (2021) by Jean-Paul Oliver</a>
 
-\- <a href="https://openstax.org/details/books/algebra-and-trigonometry" target="_blank" rel="noopener noreferrer nofollow">Algebra and Trigonometry by Jay Abramson</a>
+\- <a href="https://cdn.freecodecamp.org/curriculum/college-algebra/AlgebraAndTrigonometry-OP_1tE6R5r.pdf" target="_blank" rel="noopener noreferrer nofollow">Algebra and Trigonometry by Jay Abramson</a> - sourced from OpenStax under <a href="https://creativecommons.org/licenses/by/4.0/" target="_blank">Creative Commons Attribution 4.0 International (CC BY 4.0)</a>
+
+It is also possible to download the Algebra and Trigonometry textbook from the <a href="https://openstax.org/details/books/algebra-and-trigonometry" target="_blank" rel="noopener noreferrer nofollow">OpenStax website</a>. You will need to find the correct textbook and then download the PDF. The page numbers for the assignment are based on the first link for this book.
 
 # --assignment--
 

curriculum/challenges/english/17-college-algebra-with-python/learn-ratios-and-proportions/introduction-to-college-algebra-with-python.md

@@ -14,7 +14,9 @@ This first video includes an introduction to the course, how it will work, and h
 
 \- <a href="https://lyryx.com/subjects/business/business-mathematics/" target="_blank" rel="noopener noreferrer nofollow">Business Math, a Step-by-Step Handbook (2021) by Jean-Paul Oliver</a>
 
-\- <a href="https://openstax.org/details/books/algebra-and-trigonometry" target="_blank" rel="noopener noreferrer nofollow">Algebra and Trigonometry by Jay Abramson</a>
+\- <a href="https://cdn.freecodecamp.org/curriculum/college-algebra/AlgebraAndTrigonometry-OP_1tE6R5r.pdf" target="_blank" rel="noopener noreferrer nofollow">Algebra and Trigonometry by Jay Abramson</a> - sourced from OpenStax under <a href="https://creativecommons.org/licenses/by/4.0/" target="_blank">Creative Commons Attribution 4.0 International (CC BY 4.0)</a>
+
+It is also possible to download the Algebra and Trigonometry textbook from the <a href="https://openstax.org/details/books/algebra-and-trigonometry" target="_blank" rel="noopener noreferrer nofollow">OpenStax website</a>. You will need to find the correct textbook and then download the PDF. The page numbers for the assignment are based on the first link for this book.
 
 # --assignment--