Write a polynomial function of minimum degree with real coefficients whose zeros include those listed. Write the polynomial in standard form.
4, -8, and 2 + 5i

f(x) = x4 - 6x3 - 20x2 + 122x - 928

f(x) = x4 - 19x2 + 244x - 928

f(x) = x4 - 6x3 + 20x2 - 122x + 928

f(x) = x4 - 61x2 + 244x - 928

Question

Write a polynomial function of minimum degree with real coefficients whose zeros include those listed. Write the polynomial in standard form.
 4, -8, and 2 + 5i

 f(x) = x4 - 6x3 - 20x2 + 122x - 928 

 f(x) = x4 - 19x2 + 244x - 928 

 f(x) = x4 - 6x3 + 20x2 - 122x + 928 

 f(x) = x4 - 61x2 + 244x - 928

anonymous · Answer

@IMStuck @ShailKumar @superhelp101 someoneee please help

anonymous · Answer

The zeroes are  4, -8, and 2 + 5i and 2 -5i (This is because of 2+5i)
Now the polynomial is (x-4)(x+8)(x-2-5i)(x-2+5i). Multiply it and get a 4 degree polynomial.

anonymous · Answer

-x^4 +x^3 +13*x^2 -233*x +922

imstuck · Answer

Do you get it or do you still need more insight into this?

anonymous · Answer

It should be   x4 - 19x2 + 244x - 928

imstuck · Answer

ShaliKumar is correct.  Do you have any idea how he got that?  These can be quite tricky!