How do you graph x plus three y equals nine?

Answer 1

x+3y=9

First I would solve for y

3y=-x+9

Now divide by 3

y=-x/3 + 3

This is what is called slope - intercept form.

The y-intercept is 3. So, you have your first point (0,3)

now to make this easy - choose any number that is a multiple of 3 (other than 0). How about 3.

Plug x=3 into the equation. y=-3/3+3 => y=-1+3 => y=2

So (3,2) is another point on this equation.

Now that you have 2 points you can draw the graph since it is linear. Just draw a straight line from (0,3) to (3,2) and continue drawing to the right and to the left.