Thank you for the opportunity to help you with your question!
(x-(-5))^2(x-(4-3i))(x-(4+3i))=0 is the answer.
The multiplicity of two means that the root is raised to the 2nd power. For complex numbers that are zeros the conjugate of the number is always a zero as well. To get the conjugate of a complex number like 4-3i you just change the sign in front of the term with the i in it. So the conjugate is 4+3i. Then to write the function you just subtract the zeros from x in parantheses for each zero and multiply them all together and set equal to 0.
Please let me know if you need any clarification. I'm always happy to answer your questions.