# How do you solve #x-3y=-9# and #x+3y=3# by graphing?

##### 1 Answer

#### Answer:

Solution is

Draw the two graphs

#### Explanation:

You have two equations,

To plot this on a graph, do some transformation so that you have just

**Part 1**

You need to get those equations into the form

For the first equation,

Add 9 to both sides.

Add 3y to both sides.

Dividing both sides by 3, you get

For the second one, you do the same thing

Subtracting x from both sides,

Then divide both sides by 3

**Part 2**

Plot these two equations on the same graph

graph{(x-3y+9)(x+3y-3)=0 [-10, 10, -5, 5]}

**The coordinates of where those two lines cross will be your answer. Which will be #(-3,2)#**

Here's why the coordinates of where the two lines cross is the answer:

What the line for

So for instance, if you find the point

So if you want to find a pair of numbers

The same thing applies for more than one line. Since a point that lies on some line