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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
Answer:
See below.
Step-by-step explanation:
2a.
If a polynomial equation with real coefficients has imaginary roots, then the roots must be pairs of complex conjugate roots.
If -4i is a root, then 4i must be a root, too.
2b.
The roots of a polynomial equation can be written as first degree binomial factors, which when multiplied together will give you the polynomial.
For roots a and b, the first degree binomials are x - a and x - b.
Here the roots are -4i and 4i, so the binomials are x + 4i and x - 4i. Their product will give us the quadratic polynomial.
(x + 4i)(x - 4i) =
This is the product of a sum and a difference wuich gives the difference of two squares.
= x^2 - (4i)^2
= x^2 - 16(-1)
= x^2 + 16