Sunday, May 12, 2013

What is the factor form for x^3-x^2-6x?i just cant seem 2 get it

To start off, everything that has a factor of x in common so . . factor out the x -- this means divide each term by the x.


x(x^2 - x - 6)


Now you will go through the some what laborious process of factor the remaining trinomial . . .


make a list of factors of 6 (I'll ignore the sign for now)


1 * 6


2 * 3


No using these factors and assigning signs as you might need them to make it work . . .can you add or subract to find -1, the coeffiecient of the middle term?


1+6 = 7, -1 + -6 = -7, -1 + 6 = 5 . . .this combo just won't work


2 + -3 = -1 . . .so use 2 and -3 when we go back to rewrite the problem . . .


x(x^2 + 2x + -3x - 6) next group and factor the smaller groups


x[ (x^2 + 2x) + (-3x - 6)]


looking at (x^2 + 2x) they have a x in common so


x(x + 2)


looking at (-3x - 6), they have a -3 in common so . .


-3(x + 2) -> remember -6/-3 = +2


so now we have . . .


x[x(x + 2) + -3(x + 2)]


Notice that there is a matching (x + 2) for each grouping . . if you pull this out front .. . you will use the rest as the final factor . . . .


x (x + 2) (x + -3)


This is your factored form!

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