# How do you find the roots for #f(x) = x^2 + 12x + 20#?

##### 3 Answers

#### Explanation:

Let

#x = -10# #x = -2#

#### Explanation:

The roots are the x-intercepts. These occur where

Now we can factor the right side. We need to find factors of

Factors of

If we sum each pair, the one that gives us

Hence, we factor as:

So the roots are found as:

#x+10=0 -> x = -10# #x+2=0 -> x = -2#

Hence:

#x = -10# #x = -2#

-2 and - 10

#### Explanation:

Find 2 real roots, that are both negative (ac > 0; ab > 0), knowing their sum (- b = - 12) and their product (c = 20).

They are: -2 and - 10.

**Note** . When a = 1, we don't have to do factoring by grouping and solving the 2 binomials.