# How do you solve the equation by graphing # 3x^2 + 9x = 12#?

##### 1 Answer

Mar 15, 2016

You **could** graph the function and intersect it with a horizontal line at

#### Explanation:

On your GC you would use

And then the *intersect* -function. Make sure you set the windows at the right values. This usually takes some trying.

**Easier:**

At first we can divide everything by

Then subtract

You can factor this into:

So: