The answer is 68 because if it rose between the times it would mean you minus 7 from 75
The equation x squared minus 8x+16 represents the data in the graph because if you use the -b/2a x=4. Then if you plug in the 4 for the x in the equation you would come out with the vertex of (4,0). Hope this helps.
Can you post a clearer picture?
6×7=42 so the number missing is 42
