Solving for X (grph.calculator needed?)

[Wa1337]

Homework Statement

Solve For x: x³ + 2x² - 11x = 6

Homework Equations

N/A

The Attempt at a Solution

I got to x³ + 2x² - 11x - 6 = 0

It says to list the windows I work with (using a graphing calculator). I am unable to since I don't have one and won't be assigned one until the school year starts. How do I go about solving this function for zeros.

 

[ArcanaNoir]

This equation doesn't factor into whole numbers. :( Using the graphing calculator, you would graph it and then use the trace tool to find the roots. I believe there is a formula for cubic equations that is kind of like the quadratic equation but more complicated, but I don't know what it is.

 

[gb7nash]

Try the rational root theorem:

http://en.wikipedia.org/wiki/Rational_root_theorem

If that doesn't work and you can't use iterative methods (which probably won't give you exact roots), it's cubic formula for you.

 

[Wa1337]

Alright thank you. Will try and report back if I can :)

 

[I like Serena]

This equation doesn't factor into whole numbers. :( Using the graphing calculator, you would graph it and then use the trace tool to find the roots. I believe there is a formula for cubic equations that is kind of like the quadratic equation but more complicated, but I don't know what it is.

Try the rational root theorem:

http://en.wikipedia.org/wiki/Rational_root_theorem

If that doesn't work and you can't use iterative methods (which probably won't give you exact roots), it's cubic formula for you.

I'm afraid the Rational root theorem doesn't work in this case.
And the formula for cubic equations is pretty messy:
http://en.wikipedia.org/wiki/Cubic_function

I'm afraid graphic calculator it is!