Question

U has degree 5, zeros
1
2
, −5,
and −i, and leading coefficient 4; the zero
−5
has multiplicity 2.

Answer 1

Are we looking for the equation of U(x)?

Answer 2

yes

Answer 3

If U(x) has degree 5, that means its has 5 roots.

Roots listed in the problem are the following: 1, 2, -5, -5 (double root), -i, and then its conjugate i has to be a root if the function has real coefficients. Well, that's a total of 6 roots so I don't know how that can happen.