Question

Graphing technology can help us graph quadratic relationships more efficiently than plotting points and graphing by hand. Go to the Math Tools and open the graphing tool to graph the equation in the situation. Then answer the related question.

Josh conducts a performance test for a car. During the test, the car attains a maximum speed of 50 miles per hour. This equation models the test, where x represents time in seconds and y represents the speed in miles per hour:

y = -8x2 + 40x.

On your graph, mark the locations that represent when the car was not moving. Assuming that the test was complete when the car came to a complete stop, how long was the speed test?

Answer 1

please someone just help me

Answer 2

@AZ

Answer 3

The question is quite simple

Just graph the equation
https://www.desmos.com/calculator/t1x9rnsoos

The locations that represent when the car isn't moving is when it crosses the x-axis. That's because it's not moving right before the car starts driving in the test. And the car isn't moving when it comes to a stop at the end of the test.

To know how long the speed test was, just look at the x-value when the graph comes back to the x-axis. That's how many hours it took to complete the speed test.