Posted by **sars** on Monday, October 8, 2012 at 1:18pm.

How do you solve 8x^3-24x^2+12x-4=0?

- math -
**Steve**, Monday, October 8, 2012 at 1:24pm
first step: divide by 4 to make the numbers more manageable:

2x^3 - 6x^2 + 3x - 1 = 0

Now you know that any rational roots will be ±1 or ±1/2

So, try them out. Turns out that none of them is a root.

You can use Descarte's Rule of Signs to show that there are no negative roots, and at most three positive roots (duh).

So, now you have to fall back on the general solution of cubics (very difficult and messy) or iterative methods to get an approximate solution to any desired accuracy.

## Answer this Question

## Related Questions

- algebra - 24x^4-12x^3+48x^2/-4x 24x^4-12x^3+12(-1) 24x^4-12x^3+(-12x) 2x^4-12x^3...
- alg2 check? - solve 3(8x-2)=46-2(12x+1) 24x-6=46-24x+2 24x-6=48-24x 48x-6=48 48x...
- Math - Hello, Having trouble with this one... Solve the inequality: (2x-3)(4x)+x...
- algebra - Did I do this problem the correct way if so is there a shorter way to ...
- calculus - i need to find the derivative using chain rule: (x^2 + 2x - 6)^2 (1-x...
- math - 24x^4-12x^3+48x^2/-4x=6x^3+3x^2+12x check this for me.
- algebra - -12X^6+24x^5-18x^2/-6x^2=2x^4+24x^3-3x could some one check this for ...
- pre-calc Question on a previous question - On the question below, Bob Pursley ...
- Physica - if A=12x - 16y and B= - 24x + 10y,what is the magnitude of the vecror ...
- Algebra (Re.: Reiny) - The fact that there was that nice symmetry to the ...

More Related Questions