Since a reliable solucionario for Espinoza doesn't truly exist, the mathematically interesting alternative is to use these (which effectively replace the need for his solucionario):
If you want, I can help solve a from Espinoza's Variable Compleja (just give me the chapter and exercise number) and show the correct, rigorous solution.
It's important to clarify upfront: Many online sources claiming to have it often contain incomplete, user-uploaded, or unofficial solutions that may contain errors.