How do you solve the quadratic #z^2+1=0# using any method?

Related questions

• What does completing the square mean?
• How do I complete the square?
• Does completing the square always work?
• Is completing the square always the best method?
• Do I need to complete the square if #f(x) = x^2 - 6x + 9#?
• How do I complete the square if #f(x) = x^2 + 4x - 9#?
• How do I complete the square if the coefficient of #x^2# is not 1?
• How do I complete the square if #f(x) = 3x^2 + 12x - 9#?
• If I know the quadratic formula, why must I also know how to complete the square?
• How do I use completing the square to describe the graph of #f(x)=30-12x-x^2#?