Answer:
Start at 1 on y-intercept and go down 2 units and right 1 unit
Explanation:
First you have to graph your y-intercept (1) *which is the red dot in the graph I made for you*
Then you must use your slope (-2) to graph the rest
Since your slope is negative you have to go down from your y-intercept. In your case you are going down 2 units from your intercept. And since your slope is a whole number instead of a fraction you just go to the right 1 unit to make the coordinate (1,-1).
That is how you graph your equation.
I hope this helped!