factoring

[UrbanXrisis]

I need to find when 2x^3+x-5 is equal to zero and I'm stuck

2x^3+x-5=0
5=2x^3+x....then what?

[Hurkyl]

You sure you have the right problem?


There is a really nice theorem for finding all of the rational zeroes of a polynomial that involves the first and last terms of the polynomial, have you seen it yet?

[HallsofIvy]

Hurkyls method show that there are no rational solutions. That means that this cannot be factored with integer coefficients. There is a "cubic formula" but it is very messy. It is probably best solved numerically.

(The method I used was to graph it on my calculator, then "zoom" in on the x-intercept!)