x^3+6x^2+7x-2 find all zeros

Question

anonymous · Answer

1 doesn't work
-1 doesn't work
2 doesn't work
try -2

anonymous · Answer

once you see that $f(-2)=0$ factor as 
$$x^3+6x^2+7x-2=(x+2)(something)$$ the "something will be quadratic, use the quadratic formula or complete the square to find the other two zeros

anonymous · Answer

I actually found that -2 works, now they are asking me to factor (x^2+4x-1) and to use quadratic formula and I got 1+/- radical 5, but it seems to be wrong when I answer it in webassign

anonymous · Answer

you made a mistake in solving

anonymous · Answer

i can see from by eyeball that since you have a middle term of $4x$ that it should not be $1\pm\sqrt5$ but rather $-2\pm\sqrt5$

anonymous · Answer

$$-4\pm 2\sqrt{5}/2 is what I should have \right? I'm just confused from that point on \to get the answer$$

anonymous · Answer

that is what you get for using the quadratic formula
in any case divide all by 2 and get the answer i wrote above

anonymous · Answer

$$\frac{-4\pm2\sqrt5}{2}=-2\pm\sqrt5$$

anonymous · Answer

ahh, I totally forgot that you can reduce everything, rather than factoring out the 2 from the numerator only, Because that would leave  -2+-sqrt5/2, hence my answer -1+-sqrt5. Thanks a lot! I appreciate it.