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.
In order for the display to be rectangular the number of quarters is a row have be able to divide evenly into 50. So the number of quarters in a row can be 1,2,5,10,25,50 or 6 ways. Question 3 and 4 are done the same ways as this problem.