The slope is equivalent to -1/2. Every time the left column adds one number, the right column subtracts two. You can test this by adding in filler numbers missing in between the table. For example, between 5 and 7 would be 6. If you were subtract 2 from 10 (the previous left column answer), you would get 8. Subtract 2 from there and you would get 6. You could also test this by graphing it and simply counting how many units you’re going up or down compared to how many units you’re going left or right. Hope this helps. Lmk if you have any questions!