My teacher said it was rise over run but i don't understand.

So on a graph what she meant was that with (x,y) coordinates, you put the x coordinate first meaning you rise (go up) over run (going side to side). All it means was you have to start with the x point and then go to the y point.

Rise over run = the slope of a line segment. It does not refer to a single point. It refers to 2 points. To calculate the slope, count the numbers on the y-axis (rise) and divide by the numbers on the x-axis (run) to get from one point to the other. Positive and negative numbers matter! Slope can be either positive or negative, depending on the division math.