1. The problem statement, all variables and given/known data If the roots of x^2 - 2x + 4 = 0 are x1 and x2, what is x1^2 + x2^2? 2. Relevant equations 3. The attempt at a solution I don't think these questions can be answered by solving for x only cause there will be no real root(complex number). So I found that x1 + x2 = 2 and x1 * x2 = 4 via Vieta's theorem. And I tried solving it with the quadratic formula but as I said it hasn't got a real root.