1. Unit 4. Day 13.

2. A math “sentence” with an equal sign
Q: What is an equation? A:
A math “sentence” with an equal sign
3𝑥 + 4 = 78
3 5−𝑦 =6−3𝑦
6 𝑎+5 =7−9𝑎
Q: What does it mean to solve an equation? A:
To find the value of the variable
Q: How do we solve an equation? A:
Isolate the variable

3. 5 4 𝑥 = 𝑥− 3 4 = 1 2 = = Example A: Solve. + 3 4 + 3 4 1 2 + 3 4
𝑥− 3 4 = 1 2
+ 3 4
+ 3 4
5 4 𝑥 =
5 4 = =

4. 𝑚− 2 7 =4
Example B*:
𝑦 = 3 4
Example C*:

5. 30 7 𝑚 = 𝑚− 2 7 =4 = = = Example B*: Solve. + 2 7 + 2 7 4+ 2 7
𝑚− 2 7 =4
+ 2 7
+ 2 7
30 7 𝑚 =
4+ 2 7
30 7 = = =

6. − 1 12 𝑦 = 𝑦+ 5 6 = 3 4 = = Example C*: Solve. − 5 6 − 5 6 3 4 − 5 6
𝑦 = 3 4
− 5 6
− 5 6
− 1 12 𝑦 =
3 4 − 5 6
9 12 − 10 12
− 1 12 = =

7. 3 8 𝑥 = 1 10 1 10 ∙ 𝑥 = ÷ 3 8 𝑥 = 1 10 ∙ 𝑥 = ∙ 𝑥 = = = Example D: 3 8
3 8 𝑥 = 1 10
1 10 ∙ 𝑥 = ÷
3 8
3 8
3 8
8 3
3 8 𝑥 = 1 10
8 3 ∙ 𝑥 = ∙
8 30
4 15
1 10
8 3
8 30 𝑥 = ∙ = =

8. 6 5 ℎ = 3 4
Example E*:
− 3 2 𝑥 = 7 8
Example F*:

9. 6 5 ℎ = 3 4 3 4 ∙ ℎ = ÷ 6 5 ℎ = 3 4 ∙ ℎ = ∙ ℎ = = = Example E*: 6 5
6 5 ℎ = 3 4
3 4 ∙ ℎ = ÷
6 5
6 5
6 5
6 5 ℎ = 3 4
5 6
5 6 ∙ ℎ = ∙
15 24
5 8
3 4
5 6
15 24 ℎ = ∙ = =

10. − 3 2 𝑥+ 1 6 = 7 8 = = − 3 2 𝑥 17 24 = 𝑥= Example F*: Solve. − 1 6
− 3 2 𝑥 = 7 8
Example F*: Solve.
7 8 − 1 6
21 24 − 4 24
17 24
− 1 6
− 1 6 = =
− 3 2 𝑥
17 24 ∙ =
− 3 2
− 3 2
17 24
− 3 2 𝑥= ÷
17 24
− 2 3 34
2∙17
− 17 36
𝑥 = ∙ = − = = 72
2∙2∙2∙3∙3