Question

Joan kicked a soccer ball. The height of the ball, h, in metres, can be modelled by h =-1.2x^2 + 6x , where x is the horizontal distance, in metres, from where she kicked the ball.

Answer 1

7.5m

Explanation:

Since we are not asked what to look for we can find the maximum height reached by the ball

The ball reaches its maximum height when dh/dx = 0

dh/dx = -2.4x + 6

0 = -2.4x + 6

2.4x = 6

x = 6/2.4

x = 2.5

Get the max height

Recall:

h =-1.2x^2 + 6x ,

h(2.5) = -1.2(2.5)^2 + 6(2.5)

h(2.5) = -1.2(6.25)+15

h(2.5) = -7.5 + 15

h = 7.5

Hence the maximum height reached by the ball is 7.5m