Find a polynomial of given degree with given zeros: complex zeros

Solution
For this case we have the following roots:
4 (multiplicity 2) and i
Therefore we can create the following expression
[tex](x-4)(x-4)(x-i)(x+i)[/tex]Solving we have:
[tex](x^2-8x+16)(x-i)(x+1)=(x^{2}-8x+16)(x^{2}+1)[/tex][tex]x^{4}+x^{2}-8x^{3}-8x+16x^{2}+16[/tex]Simplifying we got:
[tex]x^4-8x^{3}+17x^2-8x+16[/tex]