Answer:
y = -x + 1
Explanation:
you know that it must be y = mx + b form so you know that b is the y-intercept and the only time it touches is on positive one so you know it needs a positive one. then to find the slope you need to use the two points that are given. Rise/Run(rise over run) it only goes up one and over -1 so divide and you get -1 for the slope.
hope this helps!