Question

Write a polynomial function of f of least degree with rational coefficients a leading coefficient of 1 and the given zeros -5 2i

Answer 1

If I'm reading this correctly, it is 
y = (x + 5)(x + 2i)(x - 2i) = (x - 5)(x^2 + 4)
which expands to
y = x^3 + 5x^2 + 4x + 20