# Finding x of this polynomial

• Mar 29th 2011, 06:04 PM
Devi09
Finding x of this polynomial
Looking for the x of this polynomial

$x^3 + 3x^2 - 40 = 0$

I tried using the factor theorem but i cant find the value that makes it 0. f( ) = 0

x should = 2.66
• Mar 29th 2011, 06:07 PM
Prove It
It doesn't factorise, so you'll have to use a numerical method, like the bisection method or Newton's method.