Exam 8: More on Functions and Graphs

Solve. -The amount of gas that a helicopter uses is directly proportional to the number of hours spent flying. The helicopter flies for 2 hours and uses 28 gallons of fuel. Find the number of gallons of Fuel that the helicopter uses to fly for 6 hours.

Write an equation of the line using function notation. -Horizontal; through $( 8 , - 3 )$

Graph the function. - $f(x)=\sqrt{x}+5$

Solve. -The cost of having a car towed is given by the linear function $C ( x ) = 3 x + 45$ , where $C ( x )$ is in dollars and $x$ is the number of miles the car is towed. Find the cost of having a car towed 15 miles.

Write an equation of the line using function notation. -Slope 0 ; through $( 0,8 )$

Solve. -The distance that an object falls when it is dropped is directly proportional to the square of the amount of time since it was dropped. An object falls 39.2 meters in 2 seconds. Find the distance the Object falls in 3 seconds.

Solve. -While traveling at a constant speed in a car, the centrifugal acceleration passengers feel while the car is turning is inversely proportional to the radius of the turn. If the passengers feel an acceleration of 20 feet per second per second when the radius of the turn is 90 feet, find the acceleration the passengers feel when the radius of the turn is 360 feet.

Solve. -A faucet is used to add water to a large bottle that already contained some water. After it has been filling for 5 seconds, the gauge on the bottle indicates that it contains 14 ounces of water. After it has been filling for 12 seconds, the gauge indicates the bottle contains 28 ounces of water. Let $y$ be the amount of water in the bottle $x$ seconds after the faucet was turned on. Write a linear equation that relates amount $y$ to time $x$ .

Solve the problem. -When a tow truck is called, the cost of the service is given by the linear function $y = 3 x + 80$ , where $y$ is in dollars and $x$ is the number of miles the car is towed. Find and interpret the slope and $\mathrm { y }$ -intercept of the linear equation.

Find the square root. - $\sqrt { \frac { 36 } { 25 } }$

Graph the function. - $g(x)=\sqrt{x+2}$

Find an equation of the line with the given slope and containing the given point. Write the equation using function notation. -Slope $- 3$ ; through $( - 4,2 )$