a) 0; The change in y is 0 because the y-values do not change. So, the slope is 0.
b) undefined; The change in x is 0 because the x-values do not change. So, the slope is undefined.
c) undefined; The change in y is 0 because the y-values do not change. So, the slope is undefined.
d) 2/5; To find slope, divide the x-value of the first point by the x-value of the second point. So, the slope is 2/5.
e) 5/2; To find slope, divide the x-value of the second point by the x-value of the first point. So, the slope is 5/2.