Least possible degree of polynomial = 5
Step-by-step explanation:
Here we have solutions -5, 1 + 4i, and -4i.
The solutions are 1 real and 2 imaginary.
Real solutions may or may not be with pair.
We know that complex solutions comes with two solutions a + ib and a - ib
So the all solutions of the polynomial are
-5 , 1+4i, 1-4i, -4i, and 4i
So minimum 5 solutions are there for this polynomial.
Polynomial with 5 solutions are of degree 5.
Least possible degree of polynomial = 5