Question 765031
All complex roots (zeroes) come in PAIRS. You need to include 2 - 8i as one of the four zeroes. Then we have the factored form of the polynomial is
(1) {{{(x-7)*(x+11)*(x-2+8i)*(x-2-8i)}}}
Just FOIL the first two factor and FOIL the last factors to get
(2) {{{(x^2+4x-77)*(x^2-4x+68)}}}
Now multiply the two quadratics of (2) and get
(3) {{{x^4+0*x^3-25x^2+580x-5207}}}
This function (3) has two real zeroes, 7 and -11 and a complex pair of zeroes, 2+8i and 2-8i