Answer
$-2$ (of multiplicity 2), $-1 + 2i, -1 - 2i$
Work Step by Step
This question asks for ALL zeros of the function
Given $P(x) = x^4 + 6x^3 + 17x^2 + 28x + 20$
See image below for synthetic division
So x = -2 is a zero with multiplicity of two
Factor and set P(x) = 0
$x^2 + 2x + 5$
$x^2 + 2x + 1 = -4$
$(x+1) ^ 2 = -4$
$x = -1 +/- 2i$
Thus the solutions are $-2$ (of multiplicity 2)$, -1 + 2i, -1 - 2i$
