You probably did this:
-3 = -2x + 1
2x = 4
x = 2
Now pretend that equation has a term "0y",
so you can write it this way:
x + 0y = 2
Now make a table of values:
x | y
|
|
|
But only substitute arbitrary values for y and solve for x:
Let y = 4, -3, 1, and 7
x | y
| 4
|-3
| 1
| 7
Substitute y=4 in x + 0y = 2
x + 0(4) = 2
x + 0 = 2
x = 2
Substitute y=-3 in x + 0y = 2
x + 0(-3) = 2
x + 0 = 2
x = 2
Substitute y=1 in x + 0y = 2
x + 0(1) = 2
x + 0 = 2
x = 2
Substitute y=7 in x + 0y = 2
x + 0(7) = 2
x + 0 = 2
x = 2
So we have this table of values:
x | y
2 | 4
2 |-3
2 | 1
2 | 7
So we plot the points (2,4), (2,-3), (2,1) and (2,7)
Then connect the points with a straight line:
So you see, it's just a vertical line. When the equation does not
contain a y, and is of the form
x = b
the graph is a vertical line that goes through (b,0). You don't need
to plot a bunch of points. I just did it to show you why it works.
Edwin
