If a paper plane is thrown from the top of a 147-foot cliff into the water below, the height of the plane at any given time can be determined by the formula h = -3t² + 147, where h is the height of the plane at t seconds. after how many seconds will the plane be at a height of exactly 20.25 feet? a. 7 seconds b. -6.5 seconds c. 6.5 seconds d. 7 seconds

c. 6.5 seconds.

Step-by-step explanation:

We have been given that a a paper plane is thrown from the top of a 147-foot cliff into the water below, the height of the plane at any given time can be determined by the formula , where h is the height of the plane at t seconds.

To find the time, when plane will be at a height of exactly 20.25 feet, we will substitute in our given formula and solve for t as:

Take square root of both sides:

Since time cannot be negative, therefore, the plane will be at a height of exactly 20.25 feet after 6.5 seconds and option 'c' is the correct choice.

f(x) is the value of the function. b is the value of the function when x equals zero or the y-coordinate of the point where the line crosses the y-axis in the coordinate plane.

step-by-step explanation:

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