Question

Please help! My teacher didn't teach us this and idk what to do

Answer 1

A. 112 feet

B. 3 seconds

C. 256 feet

Explanation:

The function
`d(t)=-16t^2+96t+112` describes the height of the quarter above the water.

When
`t=0,` then

`d(0)=-16\cdot 0^2+96\cdot 0+112\\ \\d(0)=112\ feet`

Part A. The quarter was tossed from 112 feet.

Find the vertex of parabola represented by quadratic function d(t):

`t_v=(-b)/(2a)=(-96)/(2\cdot (-16))=3\\ \\d(t_v)=d(3)=-16\cdot 3^2+96\cdot 3+112\\ \\d(3)=-144+288+112\\ \\d(3)=256\ feet`

Hence,

Part B. It will take 3 seconds to reach the maximum height.

Part C. The maximum height is 256 feet