Unit 3: Use Functions to Model Relationships

What are the slope and the y-intercept of the linear function that is represented by the equation 

 $y=9x-2$  

• The slope is –2, and the y-intercept is 9.

• The slope is 2, and they y-intercept is 9.

• The slope is 9, and the y-intercept is –2.

• The slope is 9, and the y-intercept is 2.

What are the slope and the y-intercept of the linear function that is represented by the graph?

• $The\ slope\ is\ -\frac{4}{3},\ and\ the\ y-intercept\ is\ \ 3.$

• $The\ slope\ is\ -\frac{4}{3},\ and\ the\ y-intercept\ is\ \ 4.$

• $The\ slope\ is\ -\frac{3}{4},\ and\ the\ y-intercept\ is\ \ 4.$

• $The\ slope\ is\ -\frac{3}{4},\ and\ the\ y-intercept\ is\ \ 3.$

What are the slope and the y-intercept of the linear function that is represented by the table?

• The slope is –2, and the y-intercept is 6.

• The slope is –2, and the y-intercept is 12.

• The slope is 2, and the y-intercept is 6.

• The slope is 2, and the y-intercept is 12.

 $\ 8x-2y=5?$ 
What are the slope and the y-intercept of the linear function that is represented by the equation ?

•  $The\ slope\ is\ -\frac{5}{2},\ and\ the\ y-intercept\ is\ 4.$  

•  $The\ slope\ is\ \frac{5}{2},\ and\ the\ y-intercept\ is\ 4.$  

•  $The\ slope\ is\ 4,\ and\ the\ y-intercept\ is\ -\frac{5}{2}.$  

•  $The\ slope\ is\ -4,\ and\ the\ y-intercept\ is\ \frac{5}{2}.$  

Which linear function has the greatest y-intercept?

• x + 6y = 36

• y = 15x + 5

• 3x + 8y = 24

• y = 4x + 7

A daycare facility charges a fee for every minute that a parent is late after the facility’s published closing time. The table represents the fee, y, which is dependent on the number of minutes late, x. Which of the following linear equations represents the situation?

• y = 6x + 2

• y = 6x + 36

• y = 3x + 22

• y = 24x + 36

A plumber charges a $45 fee to make a house call and then $25 for each hour of labor. The plumber uses an equation in the form y = mx+b to determine the amount to charge each customer. What is the value of m in the equation?

• 45

• 25

• 70

• 20

Which is the equation of a line that has a slope of 4 and passes through point (1, 6)?

• y = 4x - 2

• y = 4x + 6

• y = 4x + 2

• y = 4x -3

Jolon used the slope-intercept form to write the equation of a line with slope 3 that passes through the point (5, –2). His work is shown above.

• He forgot to add the b-value in step 5.

• He added 15 to both sides in step 3.

• He switched the x- and y- values in step 1.

• He multiplied incorrectly in step 2.

The graph shows the amount of water that remains in a barrel after it begins to leak. The variable x represents the number of days that have passed since the barrel was filled, and y represents the number of gallons of water that remain in the barrel.

What does the y-intercept represent?

• the amount of water that is added to the barrel each day

• the amount of water that remains in the water barrel

• the amount that the water barrel decreases each day

• the amount of water that is initially in the water barrel