1. Objective - To solve equations using the properties of equality.
Addition Property of Equality
If a = b,
then a + c = b + c or
Given a = b
and c = c
then a + c = b + c
Subtraction Property of Equality
If a = b,
then a - c = b - c or
Given a = b
and c = c
then a - c = b - c

2. x + 3 = 7
Heavier
- 3

3. x = 7
Heavier

4. x = 7
Heavier

5. x = 7
Heavier

6. x = 7
Heavier

7. x + 3 = 7
- 3 = x 4
Algebraically,
x + 3 = 7
x + 3 = 7
x = 7 - 3
x = 4
x = 4

8. Rules for Transforming Equations
1) Goal:
Isolate the variable on one side
of the equation.
2) Always perform the same operation to
both sides of an equation.
3) To undo an operation, perform its opposite
operation to both sides of the equation.

9. Solve the equations below.
1) x + 3 = 10
4) 13 = x + 5
x = 7
8 = x
2) y - 8 = 11
5) 12 = n - 3
y = 19
15 = n
3) n + 5 = 11
6) = k
14 = k
n = 6

10. Translate the sentence into an equation and solve.
1) The sum of k and 13 is 28.
k + 13 = 28
k = 15
2) Five is the difference of t and 4.
5 = t - 4
9 = t

11. Multiplication Property of Equality
If a = b, then a c = b c. or

12. Solve. 1) 3) 2) 4)

13. Division Property of Equalityor

14. Solve. 1) 3) 2) 4)

15. Solve. 1) 3) 2) 4)