Use -3, 0, 3 to find three coordinate points on 3x - y = 9

Question

I am sure I am over thinking this seeing how I can plot points, find slopes, and write line equations. Can anyone explain this to me? I have a final next week and these kinds of problems will be on it. Thanks.

Answer 1

coordinate points are (x,y) combinations.

You can plug  the given values in for 1 variable, then solve for the other variable.

 

When x = -3.

       3(-3) - y = 9

           -9 - y = 9

                -y = 18

                 y = -18

        ordered pair is (-3, -18)

 

When x = 0,

        3(0) - y = 9

               - y = 9

                  y = -9

        ordered pair is (0, -9)

 

When x = 3

         3(3) - y = 9

         9 - y = 9

            -y = 0

             y = 0

          ordered pair is (3, 0)