Assignment:
When the coefficients a,b, and c are complex numbers. Specifically, by completing the square on the left-hand side, derive the quadratic formula
z=(-b+(b^2-4*a*c)^1/2)/2*a where both square roots are to be considered when b^2-4*a*c cannot equal zero
Use the result to find the roots in the equation z^2 + 2*z+(1-i)=0.
Provide complete and step by step solution for the question and show calculations and use formulas.