2-3 Solve Multiplication and Division Equations
Name
Date
Solve: d 8
6
d
6 • 8 • 6
6
d 48
5f 45
7
7
5
• f 7(45)
5
7
5
Solve:
Multiply each side by 6
to isolate d.
[( ) ( )]
Multiply each
side by the
5
reciprocal of .
7
f 63
Check: d 8
6
(48) ?
8
Substitute 48 for d.
6
8 ⴝ 8 True
5f 45
7
9
?
5
• ( 63 ) 45
7
Check:
Substitute 63 for f.
1
45 ⴝ 45 True
Solution set: {48}
Solution set: {63}
Solve each equation. Write a justification for each step.
Then check each solution. Write your solution. Check students’ justifications.
1. 3g 24
3g
24
3 ⴝ 3
gⴝ8
?
Check: 3(8) ⴝ 24
24 ⴝ 24 True
2. 5h 30
{6}
{8}
Copyright © by William H. Sadlier, Inc. All rights reserved.
5. 2b 3.8
6. 9n 1.8
{ⴚ1.9}
9. z 2
3
13. 5a 10
6
{12}
p
5
4
7. 2.16 –7.2t
{ⴚ8}
8. 7.15 1.1w
{0.3}
11. 3.2 e
1.1
{ⴚ20}
14. 7c 28
9
4. 256 32f
{ⴚ3}
{ⴚ0.2}
10.
{ⴚ6}
3. 111 37d
{6.5}
12. 4.2 k
3.1
{ⴚ3.52}
1
15. 1 2 5d
{36}
Lesson 2-3, pages 46–49.
{ⴚ103 }
{ⴚ13.02}
3
16. 9 4 3f
{134 or ⴚ314}
Chapter 2
43
For More Practice Go To:
Solve. Show your work.
Let u ⴝ Uri’s dog’s weight. 2u ⴝ 62, u ⴝ 31;
31 lb
19. Olivia plants 435 trees in 15 rows. She plants
the same number in each row. How many trees
are in each row?
Let t ⴝ trees. 15t ⴝ 435, t ⴝ 29; 29 trees
21. The area of a rectangular plot of land is
562.48 km2. If the width of the land is 15.8 km,
what is its length? (Hint: Arearectangle ᐉw)
Let ᐉ ⴝ length. 15.8ᐉ ⴝ 562.48, ᐉ ⴝ 35.6;
35.6 km
23. The area of a triangle is 5.4 cm2.
If its base is 3 cm, what is its height?
1
(Hint: Areatriangle 2 bh)
3h
Let h ⴝ height. 5.4 ⴝ
, h ⴝ 3.6
2
3.6 cm
3
25. Marsha used 4 of the paper she bought to
print flyers for a fundraiser. If she printed
1800 flyers, how many pieces of paper did
she buy?
3
Let p ⴝ paper bought. p ⴝ 1800, p ⴝ 2400;
4
2400 papers
18. A company ships 28 boxes with 45 games
in each box. How many games does the
company ship?
g
Let g ⴝ games.
ⴝ 45, g ⴝ 1260;
28
1260 games
20. A maple tree is 3 times the height of an oak
tree. If the maple is 27 feet high, how high is
the oak?
Let h ⴝ height of oak. 3h ⴝ 27, h ⴝ 9; 9 ft
22. A forest is rectangular in shape. Its length
is 65.8 km. If the area of the forest is
3901.94 km2, what is its width?
Let w ⴝ width. 65.8w ⴝ 3901.94, w ⴝ 59.3;
59.3 km
24. A triangular flag has a height of 8.5 in.
Its area is 43.35 in.2 What is the length
of its base?
Let b ⴝ base. 43.35 ⴝ
10.2 in.
2
26. Yau and Sophia collected 3 of all the cans that
were collected for recycling. If they collected
3894 cans, how many cans were collected
for recycling?
2
Let c ⴝ cans. c ⴝ 3894, c ⴝ 5841; 5841 cans
3
27. To solve the equation 2r 30, Nina multiplied by 5 and then divided
5
by 2 to get r 75. Explain why Nina’s method works.
2r
5
2
ⴝ 30, multiply both sides by (the multiplicative inverse of ).
5
2
5
This is the same as multiplying both sides by 5 and dividing both sides by 2.
To solve
44
Chapter 2
8.5b
, b ⴝ 10.2
2
Copyright © by William H. Sadlier, Inc. All rights reserved.
17. Yoni’s dog weighs twice as much as Uri’s dog.
If Yoni’s dog weighs 62 pounds, what is the
weight of Uri’s dog?