Answer
$3,2-i,2+i$
Work Step by Step
Consider $P(x)=x^3+7x^2+17x-15=0$
In order to get the zeroes of the polynomial $P(x)$ we will have to solve as follows:
$x^3+7x^2+17x-15=(x-3)(x^2-4x+5)=0$
This gives: $(x-3)(\dfrac{4\pm\sqrt{16-20}}{2})=0$
This can be re-written as:
$(x-3)(\dfrac{4\pm\sqrt{-4}}{2})=0$
$(x-3)(\dfrac{4\pm 2i}{2})=0$
Thus the zeroes of $P(x)$ are: $3,2-i,2+i$