Algebraic extensions and the solvability of quintics.
Homological algebra, representation theory, and algebraic geometry. Where to Find Solutions (Unofficial Guides) Dummit Foote Abstract Algebra Solution Manual
For math students, by David S. Dummit and Richard M. Foote is often considered the "gold standard" of textbooks. Whether you are an undergraduate tackling group theory for the first time or a graduate student deep in Galois theory, you have likely realized that the book’s 1,500+ exercises are where the real learning happens. Algebraic extensions and the solvability of quintics