Factoring an equation

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how do i factor out 6x^2-x-1?

Guest Oct 29, 2015

+6251

+10

Best Answer

Since the constant term is -1 you know your factors are going to be

$6x^2 -x -1 = (a x + 1)(b x -1) = (ab)x^2+(b-a)x-1$

$a b =6, (b-a)=-1 \\ b=a-1 \\ a(a-1) = 6 \\ a=3, b=2$

$6x^2-x-1 = (3x+1)(2x-1)$

Rom Oct 29, 2015

Rom · Answer 1 · 2015-10-29T03:15:50

Since the constant term is -1 you know your factors are going to be

$6x^2 -x -1 = (a x + 1)(b x -1) = (ab)x^2+(b-a)x-1$

$a b =6, (b-a)=-1 \\ b=a-1 \\ a(a-1) = 6 \\ a=3, b=2$

$6x^2-x-1 = (3x+1)(2x-1)$

Melody · Answer 2 · 2015-10-29T05:22:48

Thansk Rom

I would not have done it like that but I like that logic.

To use Chris's expression, "I will put that in my tool belt"

I think that is what chris says anyway LOL