Re: factoring
stapel said:
through synthetic division (using Descartes' Law, as needed), etc, etc.
Eliz.
Descartes' Law? Isn't that related to optics? :shock:
pamela said:
I'm having a hard time figuring this one out. How do I explain to my students how to factor this: x^3-6x^2+10x-8
The answer is (x-4)(x^2 -2x+2)
Thanks!!
For your students, or for
you? :?:
\(\displaystyle x^3 - 6x^2 +10x - 8\)
Read what Eliz said.. it is important that both you and
your students understand all the methods that can be used :!:
We can do some simple manipulation of terms.
Just by looking at the answer, we can reconstruct the terms prior to grouping & factoring. (If we didn't have the answer, it would still be doable, it would just take a little longer to see what needed to be manipulate
\(\displaystyle x^3 - 2x^2 + 2x - 4x^2 + 8x - 8\)(if you simplify these terms, you will get \(\displaystyle x^3 - 6x^2 +10x - 8\)
\(\displaystyle x(x^2 - 2x + 2) - 4(x^2 - 2x + 2)\)
\(\displaystyle = (x - 4)(x^2 - 2x + 2)\)
This one, of course, is a little tricky..... it would be easier to use the rational roots test and then synthetic division instead of playing around with terms for 20 minutes