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I know that the answer is 2X+3 but I can not figure out how to get to that answer.

2007-07-26 16:26:48 · 6 answers · asked by Anonymous in Science & Mathematics Mathematics

6 answers

I would use factoring by grouping.

Multiply 2 and -6, which is -12, and find the pair of factors that give a sum of -1, the coefficient of -x. The magic pair is +3 and -4.

Because +3x - 4x = -x, then expand the polynomial as 2x^2 +3x - 4x - 6.

Now factor out the x in the first pair of terms. Then factor out the -2 in the second pair of terms. At this point, you should have.............

x(2x + 3) - 2(2x + 3) which can be factored again as (x-2)(2x+3). As you can see, 2x + 3 is one of the linear factors.

Instead of factoring, you can also use synthetic division.

Hope this helps! :-)

2007-07-26 16:42:08 · answer #1 · answered by apodosis 2 · 0 0

2x^2 -x -6
b^2-4ac = 1-4(2)(-6) = 49 which is a perfect square with root equal to 7.
So the values of the roots are (1+/- 7)/4 = 2 or -3/2
So factors are (x-2) and (x+3/2). Now you may rewrite the answer (x+3/2) as (2x +3) because either factor when set to zero will give you x = -3/2
2x^2-x-6 = (x-2)(2x+3)

2007-07-26 23:39:51 · answer #2 · answered by ironduke8159 7 · 0 1

2x^2 - x - 6
2x^2 - 4x + 3x - 6
2x(x - 2) +3(x - 2)
(2x - 3)(x - 2)

If ax^2 + bx + c, is the general eq and a,b and c are constants... to factor this, split b into two numbers that add up to b and multiply to give the product of a and c.
In the above equation, -4 and 3 add to give -1 and multiply to give -12.

2007-07-26 23:29:19 · answer #3 · answered by Anonymous · 0 1

If one factor is in fact 2x+3, then synthetic division will give the other as (x-2). Since it comes out even, this factorization is correct.

2007-07-26 23:32:31 · answer #4 · answered by Anonymous · 0 1

I would go to yahoo answers and ask the people there how to find the answer. That is what I'd do.

2007-07-26 23:29:44 · answer #5 · answered by Anonymous · 0 1

(2x+3)(?) = 2x^2-x-6

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

So multiply by (x-2)

2007-07-26 23:30:55 · answer #6 · answered by Reese 4 · 0 1

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