9 ft
Explanation:
The height of kangaroo after it jumps is represented by the function
, where
is in seconds, height is in feet.
To find the maximum height that the kangaroo jumps, we need to maximise
.
The minimum/maximum value of a quadratic expression
is given by
.
As the coeffecient of quadratic term is negative, the function has a maxima.
Maximum value =
.
∴ Maximum height = 9 ft