Answer:
y= -x +1 where the slope is -1 and the y intercept (or b) is 1.
Explanation:
y = mx + b
m the slope is -1 and b is 1.
Another way to graph it is to choose points along the map.
For example, at x = 2, y = 1, (2,1) that's a point .
for x = 4, y = -3, (4,-3) Thats another point.
Now you have two points you can draw the line.