Okay, to find the equation you must find the y-intercept and the slope.
To find the y-intercept, you must find (0,y). This is the point on the y-axis where x is 0. So, where along the y-axis is there a point? There is a point at (0,-1). Therefore, your y-intercept is -1.
To find the slope, you must do rise/run. Go to a point on the line, such as (0,-1). You must go up (or down) until you get lined up with next point on the line. You go up one time. Then, you must go right (or left) to get to the exact point. In this case, the point would be (-1,0). You go left one time.
If you go down or left when doing rise/run, the number would be negative. Since you went left, that number would be negative.
So, our slope would be 1/-1, which can also be written as -1/1.
Now, write the equation. There is always an x next to the slope. y= -1/1x
Then, put the y-intercept next to it. If it is positive, use a +. If it is negative, use a -. It is negative.
