# How do you solve #3x ^ { 2} - 90x - 192= 0#?

##### 1 Answer

Jul 15, 2017

#### Explanation:

Introduction to the test for divisibility by 3:

The sum of the digits in 90 is

Using the same method as above:

Factor out the 3

Divide both sides by 3

Notice that

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Check: