Calculate f(x) for all numbers between 0 and 10:
f(0) = −0^2 + 11(0) − 18 = -18
f(1) = −1^2 + 11(1) − 18 = -8
f(2) = −2^2 + 11(2) − 18 = 0
f(3) = −3^2 + 11(3) − 18 = 6
f(4) = −4^2 + 11(4) − 18 = 10
f(5) = −5^2 + 11(5) − 18 = 12
f(6) = −6^2 + 11(6) − 18 = 12
f(7) = −7^2 + 11(7) − 18 = 10
f(8) = −8^2 + 11(8) − 18 = 6
f(9) = −9^2 + 11(9) − 18 = 0
f(10) = −10^2 + 11(10) − 18 = -8
When the value is negative it doesn't drip, so it starts and stops dripping when the values = 0
Which is f(2) and f(9), the values are 2 and 9.