x = 3 and x = 6
When x = 3, f(3) = -(3)2 + 9(3) - 18 = -9 + 27 - 18 = 0, which means the icicle starts dripping at x = 3.
When x = 6, f(6) = -(6)2 + 9(6) - 18 = -36 + 54 - 18 = 0, which means the icicle stops dripping at x = 6.
An icicle drips at a rate that can be represented by the function f(x) = −x2 + 9x − 18, where 0 ≤ x ≤ 10 and x is the number of hours after the sun has risen. When f(x) is a negative number, the icicle is not dripping. Determine the values when the icicle starts and stops dripping.
x = −3 and x = 6
x = 3 and x = −6
x = 3 and x = 6
x = −3 and x = −6
1 answer