A polynomial equation with real coefficients has roots at x=+1 and x=2i. what is the minimum degree of the polynomial equation?

Question

Help ._. Please i no understand this.

Answer 1

When you have complex root, they have to come in pairs. So even though they only give you 2i, -2i will also be a zero. Turning these into factors.

(x-1)(x+2i)(x-2i) Is you multiply this out (you don't have to because it isn't asking) you would have x³. Therefore this is degree 3.