30% of 47.50 is 14.25 so the amount payed the person payed in total would be 33.50
0.30 x 47.50 = 14.25
47.50 - 14.25 = 33.50
the distance between (8,0) and (1,0) is 7 units
Cross multiply:
2.5 ft x 16.5 ft = 41.25 ft
now divide:
41.25 / 8.25 = 5
L = 5 feet
(n+12)(n-7) = n^2 + 5n - 84