Answer:
[tex]\textsf{1)}\quad f(x)=a(x^4-12x^3+52x^2-192x+576)[/tex]
[tex]\textsf{2)}\quad 8+i[/tex]
Step-by-step explanation:
Question 1
To form a polynomial f(x) with real coefficients given its zeros, we can use the factored form of a polynomial:
[tex]\boxed{\begin{array}{l}\underline{\textsf{Factored form of a polynomial}}\\\\y=a(x-r_1)(x-r_2)...(x-r_n)\\\\\textsf{where:}\\\phantom{ww}\bullet\;\textsf{$a$ is the leading coefficient}.\\\phantom{ww}\bullet\;\textsf{$r_1, r_2, ..., r_n$ are the zeros (roots)}.\\\end{array}}[/tex]
The number of factors corresponds with the degree of the polynomial.
Given conditions:
- Polynomial function f(x) with real integer coefficients.
- Degree: 4
- Zeros: 6 with multiplicity of 2; 4i
If a polynomial with real coefficients has a complex root (a + bi), then its conjugate (a - bi) is also a root (zero) of the polynomial.
So, given that 4i is a zero of function f(x), its complex conjugate -4i is also a zero of the polynomial.
In the context of polynomial roots, the multiplicity refers to how many times a particular root appears as a factor in the factored form of the polynomial. Therefore, given that the root 6 has a multiplicity of 2, it appears twice.
So, the factored form of polynomial f(x) is:
[tex]f(x)=a(x-6)(x-6)(x-4i)(x-(-4i))[/tex]
Expand and simplify:
[tex]f(x)=a(x^2-12x+36)(x-4i)(x+4i) \\\\f(x)=a(x^2-12x+36)(x^2+4ix-4ix-16i^2) \\\\f(x)=a(x^2-12x+36)(x^2-16(-1)) \\\\f(x)=a(x^2-12x+36)(x^2+16) \\\\f(x)=a(x^4+16x^2-12x^3-192x+36x^2+576) \\\\f(x)=a(x^4-12x^3+52x^2-192x+576)[/tex]
Therefore, the polynomial f(x) with real coefficients having the given degree and zeros is:
[tex]\Large\boxed{\boxed{f(x)=a(x^4-12x^3+52x^2-192x+576)}}[/tex]
[tex]\dotfill[/tex]
Question 2
The number of zeros of a polynomial is equal to its degree, counting multiplicities and including complex conjugate pairs.
Therefore, given that the degree of polynomial f(x) is 3 and we are provided with two zeros, 3 and (8 - i), there is one remaining zero to find.
Since the coefficients of f(x) are real numbers, complex roots occur in conjugate pairs. Therefore, if 8 - i is a root, its conjugate 8 + i must also be a root of f(x).
So, the remaining zero of f is:
[tex]\Large\boxed{\boxed{8+i}}[/tex]