Question

A hovercraft takes off from a platform.
Its height (in meters), xxx seconds after takeoff, is modeled by:
h(x)=-3(x-3)^2+108h(x)=−3(x−3)
2
+108h, left parenthesis, x, right parenthesis, equals, minus, 3, left parenthesis, x, minus, 3, right parenthesis, squared, plus, 108
How many seconds after takeoff will the hovercraft land on the ground?

Answer 1

Answer:

9 seconds

Step-by-step explanation:

The mathematical model for the given case is;

h (x) = - 3 (x-3) ^ 2 + 108

When the hovercraft lands, then its height from ground would be zero. Hence computing above equation to 0

-3 (x-3) ^ 2 + 108 = 0

-3 (x-3) ^ 2 = -108

(x-3) ^ 2 = -108 /- 3

(x-3) ^ 2 = 36

Taking square root on both sides and taking the positive only;

(x-3) = sqrt{36}

x = 6 + 3

x = 9