We want to graph the equation y = -x
And we will plug in three values for x to get three values for y. Then we can make an ordered pair and then plot those points.
I'll plug in 1, 2 and 3.
When x equals 1
y = -1
When x equals 2
y = -2
When x equals 3
y = -3
Now we have the points (1, -1), (2, -2) and (3, -3)
We can graph those points to get a line.
Below a picture can be found to see what the line will look like.