Download 9-8

Chapter 9 Quiz
Worksheets
Complete the QUIZ A & B worksheets and
use it to prepare yourself for tomorrow’s
Chapter 9 test.
9-8 Solving Integer Equation
Warm Up
Problem of the Day
Lesson Presentation
Course 1
9-8 Solving Integer Equations
Warm Up
Use mental math to find each solution.
1. 6 + x = 12 x = 6
2. 3x = 15
x
3. __
=
4
5
4. x – 8 = 12 x = 20
Course 1
x = 20
x=5
9-8 Solving Integer Equations
Problem of the Day
Marie spent $15 at the fruit stand,
buying peaches that cost $2 per
container and strawberries that cost $3
per container. She bought the same
number of containers of each fruit. How
many containers each of peaches and
strawberries did she buy?
3
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9-8 Solving Integer Equations
Today’s Learning Goal Assignment
Learn to solve
equations
containing
integers.
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9-8 Solving Integer Equations
Additional Example 1A: Adding and Subtracting
to Solve Equations
A. Solve –8 + y = –13. Check your answer.
–8
+
y = –13 –8 is added to y.
+ 8 Subtracting –8 from both
sides to undo the addition
is the same as adding +8.
y = –5
Check
+8
–8 + y = –13
?
–8 + (–5) = –13
Write the equation.
Substitute –5 for y.
?
–13 = –13  –5 is a solution.
Course 1
9-8 Solving Integer Equations
Helpful Hint
To solve the equation on the previous slide using
algebra tiles, you can add four tiles to both sides
and then remove pairs of red and yellow tiles.
This is because subtracting a number is the same
as adding its opposite.
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9-8 Solving Integer Equations
Try This: Example 1A
A. Solve –2 + y = –7. Check your answer.
–2
+2
+
y = –7
+2
y = –5
Check
–2 + y = –7
?
–2 + (–5) = –7
?
-7 = -7 
Course 1
–2 is added to y.
Subtracting –2 from both sides to
undo the addition is the same as
adding +2.
Write the equation.
Substitute –5 for y.
–5 is a solution.
9-8 Solving Integer Equations
Additional Example 1B: Adding and Subtracting
to Solve Equations
B. n – 2 = –8.
n – 2 = –8 2 is subtracted from n.
+2
+ 2 Add 2 to both sides to
undo the subtraction.
n = –6
Check
n – 2 = –8
?
–6 – 2 = –8
?
–8 = –8
Course 1
Write the equation.
Substitute –6 for n.
–6 is a solution.
9-8 Solving Integer Equations
Try This: Example 1B
B. n – 6 = –14.
n – 6 = –14 –14 is added to n.
+6
+6
Add 6 to both sides to undo the
subtraction.
n = –8
Check
n – 6 = –14
?
–8 – 6 = –14
?
–14= –14 
Course 1
Write the equation.
Substitute –8 for n.
–8 is a solution.
9-8 Solving Integer Equations
Additional Example 2A: Multiplying and Dividing
to Solve Equations
A. 4m = –20
-20
4m
___
___
=
4
4
m = –5
Check
4m = –20
?
4(–5) = –20
?
–20 = –20 
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m is multiplied by 4. Divide
both sides by 4 to undo the
multiplication.
Write the equation.
Substitute –5 for m.
–5 is a solution.
9-8 Solving Integer Equations
Try This: Example 2A
A. 3n = –15
-15
3n
___
= ___
3
3
n is multiplied by 3. Divide
both sides by 3 to undo the
multiplication.
n = –5
Check
3n = –15
Write the equation.
?
Substitute –5 for n.
3(–5) = –15
?
–15 = –15 
Course 1
–5 is a solution.
9-8 Solving Integer Equations
Additional Example 2B: Multiplying and Dividing
to Solve Equations
x
B.
= –7
3
x
__
3•
= 3 • (–7) x is divided by 3. Multiply both
3
sides by 3 to undo the division.
x = –21
Check
x
__
= –7
3
?
–21 ÷ 3 = –7
?
–7 = –7 
Course 1
Write the equation.
Substitute –21 for x.
–21 is a solution.
9-8 Solving Integer Equations
Try This: Example 2B
y
B. __= –6
4
y
__
4•
=4
4
(–6) y is divided by 4. Multiply both
sides by 4 to undo the division.
y = –24
•
Check
y
__
= –6
4
?
–24 ÷ 4 = –6
?
–6 = –6 
Course 1
Write the equation.
Substitute –24 for y.
–24 is a solution.
9-8 Solving
Insert Lesson
IntegerTitle
Equations
Here
Lesson Quiz
Solving each equation.
1. 5 + x = –6 x = –11 2. y – 9 = –7 y = 2
x = –9 x = –45
4.__
5
5. A submarine captain sets the following diving
course: dive 300 ft, stop, and then dive another
3. –6a = 24 a = –4
300 ft. If this pattern is continued, how many
dives will be necessary to reach a location 3,000
ft below sea level? 10
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