The y coordinate would become a negative or positive depending on the number. The x coordinate stays the same. For example, if the numbers were (3,2), then they the x coordinate, 3, stays the same and the y coordinate, 2, changes to -2 (negative 2).
Depends, rise over run could be considered a fraction, or if it's a number that has a whole number like one and 3/4 then you just plot the point to the best of your ability. In other words guess.
