Download ordered pair

3-1 Ordered Pairs
Warm Up
Solve.
1. x  8 = 19
2. 5 = a  2
x = 27
a=7
3. 7 + n = 24
n = 17
4. 3c  7 = 32
c = 13
5. 17y + 7 = 58
y=3
Course 3
3-1 Ordered Pairs
Problem of the Day
A moving van travels 50 miles per hour.
Use the equation y = 50x, where x
represents the number of hours. How far
will the van travel in 4.5 hours?
225 miles
Course 3
3-1 Ordered Pairs
TB P. 118-121
Learn to write solutions of equations in two
variables as ordered pairs.
Course 3
3-1 Ordered Pairs
Vocabulary
ordered pair
Course 3
3-1 Ordered Pairs
The company that makes team uniforms for a
soccer league charges a $20 fee for team
artwork and $10 for each jersey. Dominic’s
team has 14 players, and Alyssa’s team has 12
players. Find the cost for a set of jerseys for
each team.
Let y be the total cost of a set of jerseys and x
be the number of jerseys needed.
Course 3
3-1 Ordered Pairs
total cost of jerseys = $20 + $10 •
# of jerseys
y = $20 + $10 • x
Dominic’s team:
y = $20 + ($10 • 14)
y = $160
Alyssa’s team:
y = $20 + ($10 • 12)
y = $140
Course 3
3-1 Ordered Pairs
An ordered pair (x, y) is a pair of numbers that
can be used to locate a point on a coordinate
plane. A solution of a two-variable equation can
be written as an ordered pair.
The ordered pair (14, 160) is a solution because
160 = $20 + ($10 • 14).
The ordered pair (12, 140) is a solution because
140 = $20 + ($10 • 12).
Course 3
3-1 Ordered Pairs
Additional Example 1A: Deciding Whether an Ordered
Pair Is a Solution of an Equation
Determine whether each ordered pair is a
solution of y = 4x – 1.
(3, 11)
y = 4x – 1
?
11 = 4(3) – 1 Substitute 3 for x and 11 for y.
?
11= 11 
A solution since 11=11.
(3, 11) is a solution.
Helpful Hint
The order in which a solution is written is
important. Always write x first, then y.
Course 3
3-1 Ordered Pairs
Additional Example 1B: Deciding Whether an Ordered
Pair Is a Solution of an Equation
Determine whether each ordered pair is a
solution of y = 4x – 1.
(10, 3)
y = 4x – 1
?
3 = 4(10) – 1
?
3 = 39 
Substitute 10 for x and 3 for y.
(10, 3) is not a solution.
Course 3
3-1 Ordered Pairs
Additional Example 2A: Creating a Table of Ordered
Pair Solutions
Use the given values to make a table of
solutions.
y = x + 3 for x = 1, 2, 3, 4
Course 3
x
x+3
y
(x, y)
1
1+3
4
(1, 4)
2
2+3
5
(2, 5)
3
3+3
6
(3, 6)
4
4+3
7
(4, 7)
Helpful Hint
A table of solutions
can be set up
vertically or
horizontally.
3-1 Ordered Pairs
Additional Example 2B: Creating a Table of Ordered
Pair Solutions
Use the given values to make a table of
solutions.
n = 6m – 5 for m = 1, 2, 3
m
1
2
3
6m – 5 6(1) – 5 6(2) – 5 6(3) – 5
n
1
7
13
(m, n)
Course 3
(1, 1)
(2, 7)
(3, 13)
3-1 Ordered Pairs
Additional Example 3A: Consumer Math Application
A salesman marks up the price of everything
he sells by 20%. The equation for the sales
price p is p = 1.2w, where w is wholesale cost.
What will be the sales price of a sweater with
a wholesale cost of $48?
p = 1.2(48) The wholesale cost of the sweater
before tax is $48. Multiply.
p = 57.6
The $48 wholesale sweater will cost the
customer $57.60, so (48, 57.60) is a solution
of the equation.
Course 3
3-1 Ordered Pairs
Additional Example 3B: Consumer Math Application
A salesman marks up the price of everything
he sells by 20%. The equation for the sales
price p is p = 1.2w, where w is wholesale cost.
What will be the sales price of a jacket with a
wholesale cost of $85?
p = 1.2(85) The wholesale cost of the jacket
before tax is $85. Multiply.
p = 102
The $85.00 wholesale jacket will cost the
customer $102, so (85, 102) is a solution of
the equation.
Course 3
3-1 Ordered Pairs
Lesson Quiz: Part I
Determine whether each ordered pair is a
solution of y = 4x  7.
1. (2, 15) no
2. (4, 9) yes
3. Use the given values to make a table of
solutions. y = 4x  6 for x = 2, 4, 6, 8, and 10
Course 3
x
4x – 6
y
(x, y)
2
4(2)  6
2
(2, 2)
4
4(4)  6
10
(4, 10)
6
4(6)  6
18
(6, 18)
8
4(8)  6
26
(8, 26)
10
4(10)  6
34
(10, 34)
3-1 Ordered Pairs
Lesson Quiz: Part II
4. A plumbing company charges $50 for a service
call and $15 per hour. They went on a 3-hour
job. How much did the company earn?
Write the equation and solve.
c = 15n + 50; $95
Course 3