I'm attaching an Excel document with a graph. But to consider the graph here:

This equation falls into the form of a linear equation. So you expect the line to be a straight line. Find where the x value is 0, which will tell you the y-intercept. The slope (the number in front of the x) is negative, so you expect the line to decrease from left to right.

I just chose random values to show what the line looks like. For a linear equation, you do not need to choose more than 2 values. This is because a straight line can be drawn after two points on a graph are made.