2x^2+13x-7=

Or is it prime?

2x^2+13x-7=

Or is it prime?

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Middletown, CT

Hi again David;

2x^{2}+13x-7

For the FOIL...

FIRST must be (2x)(x)=2x^{2}

OUTER and INNER must add-up to 13x

LAST must be (7)(1) or (1)(7) and one number must be negative.

(2x-1)(x+7)

Let's FOIL...

FIRST...(2x)(x)=2x^{2}

OUTER...(2x)(7)=14x

INNER...(-1)(x)=-1x=-x

LAST...(-1)(7)=-7

2x^{2}+14x-x-7

2x^{2}+13x-7

Woodland Hills, CA

Another way of looking at it.

2 X^{2} +13X -7

If this is factorable then

there should be 2 integers whose difference is +13, and product - 14, they are +14, -1

2X^{2} + 14X - X - 7 =2X ( X +7) - ( X + 7 ) = ( 2X - 1 ) ( X + 7)

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