Ok, so you got the parent function y = x^2 and it changed to y = x^2 -8
#'s inside the parenthesis would move it left or right and #'s outside the parenthesis would move it up or down. Since there are no parenthesis the x coordinate is 0, hence it doesn't move left or right. Because of this we know that the graph will be moved up or down. Now we look to see is the # negative or positive. If negative, we move it down. If positive, we move it up. Looking at this problem, we see that it will move it down. Next look at the #. This will indicate how <em>much</em> you will move the graph. In this problem, we will move the graph down 8.
Therefore,
When you change the graph y = x^2 to y = x^2 -8, you are moving the graph down 8.
