Pre Calculus Linear Functions

The graph of y=f(x) is a line in the xy-plane that passes through the point (0, -4) and has a slope of 4. Which of the following equations could define the function f?

• f(x)=-4x+4

• f(x)=4x-4

• f(x)=1/4x-4

• f(x)=1/4x+4

Which of the following could be an equation for the graph shown in the xy-plane?

• f(x)=(3/4)x+3

• f(x)=-(3/2)x+3

• f(x)=-(3/4)x+3

• f(x)=(3/2)x+3

The graph of a line in the xy-plane has a positive slope and intersects the y-axis at a point that has a negative y-coordinate. Which of the following could be an equation of the line?

• -3x+2y=-5

• -3x+2y=5

• 3x+2y=-5

• 3x+2y=5

In the xy-plane, line k intersects the y-axis at the point (0,3) and passes through the point (4,0). If the point (16, z) lies on the line k, what is the value of z?

• -9

• 2.25

• 2.95

• 15

In the xy-plane, line k has a slope of 1/2. If the line m is perpendicular to line k, which of the following could be an equation of line m?

• 6x+12y=36

• 4x-2y=17

• 3x-6y=14

• -10x-5y=20

The graph in the xy-plane of the linear function f contains the point (3,4). For every increase in 3 units in x, f(x) decreases by 5 units. Which of the following equations defines the function?

• f(x)=-(5/3)x+9

• f(x)=-(3/5)x+(29/5)

• f(x)=(5/3)x-1

• f(x)=(3/5)x+(11/5)

The population of the the striped zoolump in a certain area can be modeled by the function Z(t)=100-15t, where Z(t) is the population of the striped zoolump t years after 2032. Of the following, which is the best interpretation of the equation Z(6)=10?

• The striped zoolump population in this area is predicted to be 10 in the year 2038.

• The striped zoolump population in this area is predicted to be 6 in the year 2042.

• The striped zoolump population in this area is predicted to be 10 in the year 2026.

• The striped zoolump population in this area is predicted to be 6 in the year 2042.

Joe earns $11.50 per hour at his part time job. When he works h hours, he earns 11.50h dollars. Which of the following expressions gives the amount, in dollars, Joe will earn if he works 5h hours?

• 57.50+5h

• 57.50

• 11.50(5h)h

• 5(11.50h)

The equation T(h)=5h+15 represents the cost of snowboarding at White Top, where T(h) is the total cost after snowboarding for h hours, and h represents the hours you rent for. How long did Sam snowboard if the total spent was $32.50?

• 4.5 hours

• 4 hours

• 3.5 hours

• 3 hours

A cell phone plan charges $45 per month for a line of service plus .25 cents per text sent. Which of the following gives the total cost c, in dollars, of a phone plan that sends t text messages?

• c = .25t + 45

• c = 45 - .25t

• c = 45.25t

• c = 45t + .25