What books do you recommend if I want to study complex numbers from scratch? I have studied calculus and linear algebra,but I still know little about complex numbers.
I intend to know a little about complex numbers at first, then I'll try to study functions of a complex variable
 A: Check this lecture notes http://www.doc.ic.ac.uk/~mpd37/teaching/2015/145/notes_c_linalg.pdf
The first chapter should be enough for you.
The appendix of Linear Algebra by Friedberg also contains an introduction of complex numbers.
A: I would highly recommend this book:
Complex Variables: Introduction and Applications Second Edition (Cambridge Texts in Applied Mathematics) by Mark J. Ablowitz
A: Alfors: complex analysis is quite good and compact. 
For a more detailed book try "Visual complex analysis". 
A: I would strongly recommend H.A. Priestley Introduction to Complex Analysis (Oxford University Press).
It is easy to read and provides a great number of examples to every topic covered on the theory. The first chapter deals with complex numbers and algebra in the complex plane, and it is a concise introduction to develope the theory of complex analysis on one variable afterwards.
Also, one thing I really like from this book is that the author marks the most common mistakes made by students, so it warns you to not stumble on common pitfalls.
