9. The slope for this one is 21 bc y1-y2/x1-x2 is the slope formula and this can be used between any two points (I used the first two) -30-(-54)/ 7-11 which is -84/-4= 21
10. Rate of change is the same thing as slope so 4.5-5/18-20 which is -0.5/-2 which means the rate of change is 2.5
11. 23-39/1-3 which is -16/-2 which means the rate of change is 8
12. 5/4 is 1.25 so the sports drink costs 1.25$ each
Hope this helped :)