Solutions to exercises from the several standard college textbooks described below are available on each textbook's web page. Click on the textbook icon to go to the page and access the PDF files.
This is an excellent introductory undergraduate text. Solutions to all the exercises from chapters 1 through 9 (The Quadratic Reciprocity Law) of the 5th edition are available for download.
This is an excellent undergraduate introductory text. Solutions to all exercises of the 11th edition from Chapters 1-9 are available for download, including numerous MATLAB code snippets used to solve many of the problems.