URGENT!
Find a polynomial function​ f(x) of least degree having only real coefficients and zeros as given. Assume multiplicity 1 unless otherwise stated.
zero of 3​ (multiplicity 2) and zero 4i
the answer is x^4-6x^3+25x^2-96x+144, but I have no clue how to find the answer, so if someone could explain that to me, that would be awesome.