Find the slope of the line passing through the pair of points. (–4, 5) and (0, 2)

You would need to draw a graph or get some graph paper and plot those points. Then calculate the rise and the run. Rise is over the run. Then that is your slope. You get the rise by counting how many units up or down it takes to get to the point, and for the run, you count how many units across it is to get to the point. don't forget, if your units are going in a negative direction, then the number will be negative.

The equation is (y2-y2)/(x2-x1), making sure to be constistant with which pair is 1 and 2. So let's say (0,2) is 1 and (-4,5) is 2. It looks like this:
(5-2)/(-4-0)=3/(-4)= -3/4 which is your answer

What's the denominator

If gravity is one third on mars then weight also one third on mars