What are the real zeros of f (x) = x^3 + 2x^2-5x-6

First of all Horner

First we try with - 3

1. 2. - 5. - 6.

-3. 3. 6

1. - 1. - 2. 0

To verify: - 3^3+2*-3^2+15-6=0

Now we have this equation

(X+3) * (x^2 - x - 2) = 0

I dont know If you know sum and product but that is the easiest way so sum = 1 product = 2 so 2 and - 1 are the answers.

You can do this too by this way : b^2-4ac = D

X = (-b (+or-) d^1/2) / 2a

So all the zeros

2, - 1 and - 3

If you want more explanation, send me a comment x