2b² + 13b - 7
First you multiply the first and last number together, which is 2 and 7.
2 · 7 = 14
Now that you got 14, you try to find all the factors of 14 and see if any of them add up to or subtract to 13.
14:
1 · 14 = 14
2 · 7 = 14
Your factors are 1, 2, 7, and 14. 14 and 1 subtract to 13, so you can replace 13b with this:
2b² + 14b - 1b - 7 (it is not -14b + 1b because 13b is positive)
Next you factor the equation separately.
2b(b + 7) - 1b - 7
2b(b + 7) - 1(b + 7)
(2b - 1)(b + 7)
