A golfer hits a golf ball. The function
d(t) = –2t2 + 7t + 4
most closely represents the height(h) of the golf ball in feet after t seconds. How
long is the golf ball in the air?

The golf ball was in the air for 4 seconds.

Step-by-step explanation:

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

.

This polynomial has roots such that , given by the following formulas:

In this question:

We have to find the amount of time it takes for the ball to hit the ground. We have that:

Which is a quadratic equation with .

How long is the golf ball in the air?

We have to find t for which

So

Time is a positive measure, so t = 4.

The golf ball was in the air for 4 seconds.