Proportional Relationships
What equation shows a proportional relationship between x and y?
A. y = 4x
B. y = 4x + 2
C. y = x – 4
D. y = 3x – 3
y = 4x
Find the slope between (2,5) and (4,9).
2
Write the slope-intercept form: slope = 2, y-intercept = 3.
y = 2x + 3
A car travels 120 miles in 3 hours. What is the speed?
40 mph
Which set of ordered pairs represents a function?
A. {(1,2), (2,3), (3,4)}
B. {(1,5), (1,7), (2,8)}
A — each input (x) has only one output (y).
A recipe calls for 3 cups of flour for every 2 cups of sugar. What is the constant of proportionality (k)?
1.5
Find the slope and y-intercept of the line passing through (0,–4) and (3,5).
Slope = 3; y-int = (0,–4)
The line passes through (0, –5) with slope 4. Write its equation.
y = 4x – 5
A plumber charges $50 for a visit plus $75 per hour. Write the cost equation.
y = 75x + 50
True or False: The graph of a vertical line represents a function.
False
The graph of a proportional relationship always passes through which point?
The origin (0,0)
The school’s choir is traveling to a music festival, and the festival charges a fee for each choir member.
The bus fee is $200.
The team’s total cost will be $680 for 8 choir members.
The team’s total cost will be $1,020 for 12 choir members.
Which equation represents the total charges in dollars, y, for a group of x choir members?
a) y = 200x
b) y = 85x + 200
c) y = 80x + 200
d) y = 70x + 200
B) 85x + 200
Write the equation of a line passing through (2,4) and (4,8).
y = 2x
A water tank fills at a rate of 8 liters/min. How long to fill 96 liters?
12 minutes
Explain in your own words how to determine if a relation is a function.
Each x-value must pair with exactly one y-value.
y varies directly with x. If y = 24 when x = 8, what is the value of y when x = 9?
27
A group of points {(–2,8), (0,6), (2,4)} all lie on the same line. Find the slope and y-intercept.
Slope = –1, y-int = 6
If y = 5x + 12, what is the y-intercept?
(0,12)
A cell phone plan costs $30/month plus $0.05 per text. Write an equation.
Y = 0.05x + 30
Which table represents a function?
A. x: 1,2,3 → y: 2,4,6
B. x: 1,1,2 → y: 3,4,6
A- X does not repeat
Is the following table proportional, why?
x - 1 5 10 50
y- 5 25 50 250
Yes, all points show the same rate of 5.
A plumber charges $50 to make a house call then charges $25 per hour for labor.
A) Write an equation for the situation y= mx+b
B) How much does it cost for 3 hours of labor?
C)If the plumber charges $200, how many houses did he work?
A) y= 25x + 50
B) $125
C) 6 hours (Gross)
A line has slope –2 and passes through (3,4). Write the equation in slope-intercept form.
y= -2x +10
Which situation represents a proportional relationship?
A.Maria gets paid $9.20 per hour plus a $100 bonus.
B. Grocery delivery charges $1.50 per pound of groceries and a one-time $5 fee.
C. Netflix charges $11.99 per month plus $1.99 tax per month.
D. Annie started with $275 and saved $50 each month.
C - Has 2 slopes
Which statement is true about the table below?
X -4 -3 -2 -1 0
Y 5 5 5 5 5
A) It is a function because each input has exactly one output.
B)It is not a function because each output has more than one input.
C)It is a function because each output contai
D)It is not a function because the ratio between y and x is not constant.
A