## anonymous 5 years ago Find the zeros of the function x^2 - x-4

Do you know how to factor this equation?

2. anonymous

Yes but my problem is, is that I can't think of anything that added toger is 1 and multi to get 4

Hm. Fair enough. So there are a couple of ways to approach this. Do you know the quadratic formula?

4. anonymous

yes -2 +- $-b +_\sqrt{b^2 - 4ac} \over 2a$

Right. Do you know what a, b, and c are in your equation?

6. anonymous

yes a is 1x^2 b is 1x and c is 4

Close, a, b, and c are the coefficients -- so a is 1, b is -1, and c is -4. Remember that a minus sign is part of the coefficient :) Can you plug those in?

8. anonymous

yeah I get $1 \pm \sqrt{15} \over 2$

Right-o. And there are your two zeros.

10. anonymous

what are the two zeros?

The quadratic equation describes two results: $x = \frac{1 + \sqrt{15}}{2}$ and $x = \frac{1 - \sqrt{15}}{2}$ Those are the two zeros of the equation.

12. anonymous

oh, ok thanks alot

No problem, glad to help :)

14. anonymous

wouldn't this be 17 instead of 15?