Question

Hello, I need some help with this homework question, please?HW Q24

Answer 1

Given:

`h=-3t^2+147`

Required:

We need to find the number of seconds will the plane be at a height of 20.25 feet.

Step-by-step explanation:

Substitute h = 20.25 in the equation.

`20.25=-3t^2+147`

Subtract 147 from both sides of the equation.

`20.25-147=-3t^2+147-147`

`-126.75=-3t^2`

Divide both sides of the equation by -3.

`(-126.75)/(-3)=(-3t^2)/(-3)`

`42.25=t^2`

Take square root on both sides.

`\pm√(42.25)=√(t^2)`

Time is of positive value.

`√(42.25)=t`

`6.5=t`

Final answer:

After 6.5 seconds the plane will be at a height of 20.25 feet.