To find the slope of two points, we have to first assign our points as x1, y1 and x2, y2.
In our problem,
x1 = 2 and y1 = 5
x2 = 0 and y2 = -4
We know that that slope = y2 - y1 / x2 - x1. Let's plug our numbers into this formula.
Slope = -4 - 5 / 0 - 2 = -9 / -2 = 9 / 2