X³ - 12x² + 35x
x(x² - 12x + 35)
x(x-5)(x-7)
Feet
_____
second
10 feet
________
16 second
equals
.625 feet per second
Each year 107.2%increase of budget
first year 500 * 1.072 = 536
second year 536 * 1.072 = 574.592
third year 574.592 * 1.072 = 615.962624
..
..
sixth year 707.854392 * 1.072 = 758.819908
or you can just (1.072)^6 * 500 = 1.517639816659862 * 500 = 758.8199083299308
bingo........
4/7 5/8 6/9 are some possible answers