This is a horizontal line at y = -3. If you want to find it mathematically, you could find the slope (y2-y1)/(x2-x1) and you would get 0 over 5, so you know the slope is zero. Pick either point and substitute the numbers into point-slope formula. I went with (3, -3) and got (y - -3) = 0(x-3). The right side is just 0, and if you subtract three from both sides to isolate y, you get the equation y = -3.