If you start at point (0,0) and go up two over one (rise over run) to the left, you’ll be at (-1,2). Go up two over one again to the left to get to (-2,4). Your equation would be: y=-2x+0 (0 because you started at 0 so your y-intercept is 0) though since it’s +0 you can leave that out and have y=-2x. It’s a negative slope because the line would be going down to the right.
