How do you factor 2x^2 + 7x-42x2+7x4?

1 Answer
Aug 28, 2016

2x^2+7x-4=(2x-1)(x+4)2x2+7x4=(2x1)(x+4)

Explanation:

Use an AC method:

Find a pair of factors of AC=2*4=8AC=24=8 which differ by B=7B=7

The pair 8, 18,1 works.

Use this pair to split the middle term and factor by grouping:

2x^2+7x-42x2+7x4

=2x^2+8x-x-4=2x2+8xx4

=(2x^2+8x)-(x+4)=(2x2+8x)(x+4)

=2x(x+4)-1(x+4)=2x(x+4)1(x+4)

=(2x-1)(x+4)=(2x1)(x+4)