# How do you factor the expression x^2-3x-10?

Mar 31, 2016

(x + 2)(x - 5)

#### Explanation:

$y = {x}^{2} - 3 x - 10.$
Find a factor pair of (-10), that has a sum of (-3).
The pair numbers have opposite signs because ac < 0.
Factor pair of (-10) --> (2, -5). This sum is - 3 = b.
Then, the 2 numbers are: 2 and -5.
y = (x + 2)(x - 5)