Baswically find the slope of each line slope=rise/run
for the graph we see that it rises 120 over 2 hours or 120/2 or 60mph
for the other one is where miles is rise and hours is run 2 hours to 90 miles 3 hours to 135 miles change from 2 to 3 is 1 hour change from 90 to 135 is 45 miles so 45mph
