form a polynomial f(x) with real coefficients having the given degree and zeros.

Question

degree: 4; zeros: -1, 2, and 1-2i.

I got an exam tomorrow, i would appreciate any kind of help, thank you.

Answer 1

You are given 2 real roots and one complex.
As I noted before, complex numbers come in pairs,
so there has to be another one, 1+2i

so we have
f(x) = (x+1)(x-2)(x-1-2i)(x-1+2i)

multiply the last two brackets, the i's will drop out

Answer 2

thank you again, life saver