How do you factor without a computer? (Obviously, I used a computer).

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- December 10th 2012, 10:05 AMMSUMathStdntFactor a cubic without using CAS
How do you factor without a computer? (Obviously, I used a computer).

- December 10th 2012, 10:24 AMtopsquarkRe: Factor a cubic without using CAS
Are you aware of the Rational Root Theorem?

For convenience I'm going to divide the polynomial by 6:

Possible rational roots to this polynomial equation are:

That gives you 12 possible rational roots that you can check.

If you don't know that one, then you're probably stuck with Cardano's method. (Cardano's method is about 1/2 way down the page.)

-Dan - December 10th 2012, 10:26 AMPlatoRe: Factor a cubic without using CAS