1. Homework Corrections (page 1 of 5)
A#2 / Review of Pre-Algebra Worksheet
1. possible answers:
8 more than x;
the sum of x and 8
3. possible answers:
the difference of g
and 4; 4 less than g
5. 7
7. 1
9. y – 4; 5; 2
11. y + 5; 14; 11
19.
21. >
25.
27. 3
29. 4
30.
31. 0
32. undefined
35.
37. negative
39. positive
● 3 ● 3; 27

2. Homework Corrections (page 2 of 5)
A#2 / Review of Pre-Algebra Worksheet
42. -(2 ● 2 ● 2 ● 2); -16
43. (-5) ● (-5) ● (-5); -125
49. 4
51. 3
55. <
57. =
59. rational Q; integer Z;
terminating decimal
61. rational Q;
66. 6
(a – 5)

3. Homework Corrections (page 3 of 5)
A#2 / Review of Pre-Algebra Worksheet
75. possible answer:
7(89) = 7(80 + 9)
= = 623
77. 4a
79. 5c2 + 3c
81. 5q2 + 18q – 3
83.
85. ●
87. none
88. IV
89. II ●

4. Homework Corrections (page 4 of 5)
A#2 / Review of Pre-Algebra Worksheet
93. (-2, -5); (-1, -4);
(0, -3); (1, -2);
(2, -1); line
95. (-2, -4); (-1, -1);
(0, 0); (1, -1);
(2, -4); U shape ● ●

5. Homework Corrections (page 5 of 5)
A#2 / Review of Pre-Algebra Worksheet
; (-6, -4); (-3, -3);
(0, -2); (3, -1); (6, 0); line ●

6. Lesson Objective: I will be able to …
Solve one-step equations in one variable by
using addition or subtraction
Language Objective: I will be able to …
Read, write, and listen about vocabulary, key
concepts, and examples

7. Page 1
An equation is a mathematical statement that two expressions are equal.
A solution of an equation is a value of the variable that makes the equation true.
To find solutions, isolate the variable. A variable is isolated when it appears by itself on one side of an equation, and not at all on the other side.

8. Inverse Operations Operation Inverse Operation Addition Subtraction
Isolate a variable by using inverse operations which "undo" operations on the variable.
An equation is like a balanced scale. To keep the balance, perform the same operation on both sides.
Inverse Operations
Operation
Inverse Operation
Addition
Subtraction
Subtraction
Addition

9. Example 1: Solving Equations by Using Addition
Page 2
Solve the equation. Check your answer.
A. y – 8 = 24
Since 8 is subtracted from y, add 8 to both sides to undo the subtraction.
y = 32
Check
y – 8 = 24
To check your solution, substitute 32 for y in the original equation.
32 – 
= z – 7 16 5 B.
Since is subtracted from z, add
to both sides to undo the subtraction. 7 16 + 7 16
Check
= z – 7 16 5 12 16
= = z 3 4 3 4 5 16 7 –
To check your solution, substitute
for z in the original equation. 3 4  5 16

10. Solve the equation. Check your answer.
Your Turn 1
Page 2
Solve the equation. Check your answer.
n – 3.2 = 5.6
Since 3.2 is subtracted from n, add 3.2 to both sides to undo the subtraction.
n = 8.8
Check
n – 3.2 = 5.6
To check your solution, substitute 8.8 for n in the original equation.
8.8 – 

11. Example 2: Solving Equations by Using Subtraction
Page 3
Solve the equation. Check your answer.
A. m + 17 = 33
– 17 –17
Since 17 is added to m, subtract 17 from both sides to undo the addition.
m = 16
Check
m + 17 = 33
To check your solution, substitute 16 for m in the original equation. 
B = t + 1.8
– – 1.8
Since 1.8 is added to t, subtract 1.8 from both sides to undo the addition.
2.4 = t
Check
4.2 = t + 1.8
To check your solution, substitute 2.4 for t in the original equation. 

12. Solve the equation. Check your answer.
Your Turn 2
Page 3
Solve the equation. Check your answer.
–5 = k + 5
– – 5
Since 5 is added to k, subtract 5 from both sides to undo the subtraction.
–10 = k
Check
–5 = k + 5
To check your solution, substitute –10 for k in the original equation.
–5 –10 + 5
–5 –5 

13. Remember that subtracting is the same as adding the opposite
Remember that subtracting is the same as adding the opposite. When solving equations, you will sometimes find it easier to add an opposite to both sides instead of subtracting.

14. Example 3: Solving Equations by Adding the Opposite
Page 4
Solve –
+ p = – 2 11 5
Check your answer. + 5 11 5 11
Since – is added to p, add to both sides.
p = 3 11
Check
+ p = – 2 11 5 –
To check your solution, substitute for p in the original equation. 3 11 2 5 11 – 3 + 2 11 – 

15. Since – is added to z, add to both sides. + 3 4 z = 2
Your Turn 3
Page 4 3 4 5 4
Solve –
+ z = Check your answer. –
+ z = 5 4 3 3 4
Since – is added to z, add to both sides. + 3 4
z = 2
Check
+ z = 5 4 3 –
To check your solution, substitute 2 for z in the original equation. – 5 3 4
+ 2 5 4 

16. decrease in population
Example 4: Population Application
Page 5
Over 20 years, the population of a town decreased by 275 people to a population of 850.
Write and solve an equation to find the original population.
original population
minus
current population
decrease in population is
p – d = c
p – d = c
Write an equation to represent the relationship.
p – 275 = 850
Since 275 is subtracted from p, add 275 to both sides to undo the subtraction.
p =1125
The original population was 1125 people.

17. Page 1

18. Classwork
Assignment #2
Holt 2-1 #2, 5, 8, 11, 14, 17, 20, 25, 49