How do you factor completely $15x^2 + 7x - 2$ ?

Question

6424 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-08-28T19:32:13

$15x^2+7x-2=(5x-1)(3x+2)$

Given:

$15x^2+7x-2$

Use an AC method: Find a pair of factors of $AC=15*2=30$ which differ by $B=7$ .

The pair $10, 3$ works.

Use this pair to split the middle term then factor by grouping as follows:

$15x^2+7x-2$

$=15x^2+10x-3x-2$

$=(15x^2+10x)-(3x+2)$

$=5x(3x+2)-1(3x-2)$

$=(5x-1)(3x+2)$

How do you factor completely 15x^2 + 7x - 215x^2 + 7x - 2?