Y=-2/3x-1
Because the line is going in a downward slope (left to right) then one can infer that it is a negative slope.
Now that you know it’s a negative slope you want to first find your rise over run to find your slope. Start from one of the points given (since it is a negative slope it’s fall and run). Let’s start at point (-3,1) and go to (0,-1). Let’s fall 2 times and run 3 times.
Now you have the fall over run which is -2 (because you went down) over 3. This would then be the fraction -2/3. Now you want to find your y-intercept (where the line intersects with the y-axis). Observe the line and you can see it intersects at point (0,-1). Your y-intercept is -1.
Now that you have your fall over run (or slope) and your y-intercept you want to put it in slope-intercept form (y=Mx+b) M being your slope, x being your x value, and b being your y-intercept. So plug in and get y=-2/3x-1