the function is x^2-9, so all you have to do is replace x with a number. for example, 2.
so 2^2-9 is -5. the plot would be 2, -5. basically, plug in a number to be the x coord, and whatever number you get will be your y coord.
after you graph a few plots (doing the same thing above), draw a line through all of them.
if the line goes up towards the right top corner, it's increasing. if it goes down the right bottom corner, it's decreasing.
