If you go down the y-value is negative. Use the equation of rise over run which is Y2-Y1 divided by X2-X1. If the graph is rising from left to right like climbing a hill the slope is positive on a graph you could count up y units divided by right x units.
Examine the equation for the line which Excel is now displaying overlaid on the scatter plot.
5 Steps for Finding Slope from a Graph Worksheet Example Find the change in the y-values. We get slope by dividing the diffference of coordinates on the vertical axis y by the difference of the coordinates on the horizontal axis. Remember that the slope of a line never changes so. The equation will be in the form of y mx b where m and b will be.