Well, to find slope of 2 points you need to use the point-slope formula: y2-y1/x2-x1. I attached a picture of my work so you can see what i'm talking about, but i'm going to explain what I did.
1. I labeled the coordinate pairs with x1, y1 and x2, y2. Since we know a coordinate pair looks like this (x,y), we take the first X and Y values and label them x1 and y1. Then, we take the second set of X and Y values and label them x2 and y2.
2. I plugged the numbers in where they belong in the formula. For example, when you label x1 should be -2. So on our formula, all we do is replace x1 with -2. Do that with all your numbers until the whole formula is filled in.
3. Then, solve it. You should get 0/-24 and you should always simplify your answer. However, in this situation, you cannot simplify. So, your answer is 0/-24.
Hope this helps :)