You can solve this several different ways, but I’ll show you using rise over run. As you can see, you need to rise 4 to get to the point (0,4) from the point (2,0). Then, you go two units to the left getting 4 as the rise and -2 as the run. Now you divide 4 by -2 to get -2 as the slope.
Hope that helps and please let me know if you need more help!
Answer: Then you turn the 6 to a 4 and the 2 into a 4 also. Because Oliver wanted the free throw and the free throw he missed turn both equal so you divide 8 with 2 and get 4.