1. Today’s goal:
Solving equations with symbols instead of pictures.

2. 1).
Take away
Take away
2x = 9
- 3
- 3
2x = 6 2 2
x = 3

3. 2).
Take away
Take away
2 + 4x = 6 + x
- x
- x
Take away
Take away
2 + 3x = 6
- 2
- 2
3x = 4
4/3 = 1.33 3 3
x = 1.3

4. how do you show it in symbols?
When you have to flip both sides,
how do you show it in symbols?

5. 5).
How can you represent this in symbols? -
x = 4
flip
flip
x = - 4

6. Take the opposite of both sides.
For example:
Method A:
-( )
- x = 4 -
flip
flip
x =
- 4
Take the opposite of both sides.

7. What other operations would make something flip?

8. What operation is being used in these problems?
1).
4).
2).
The operation is…
Multiply by -3
3).

9. What operation would just take the opposite?
1).
4).
2).
The operation is…
3).
Multiply by -1

10. What operation is being used in these problems?
1).
The operation is…
Divide by -4
2).
3).

11. What operation would just take the opposite?
1).
4).
2).
The operation is…
Divide by -1
3).

12. Multiply both sides by -1
Back to your handout:
Method B:
-1• 1 -
x = 4
• -1
flip
flip
1x =
- 4
x = - 4
Multiply both sides by -1

13. 1 - x = 4 1x = - 4 x = - 4 Divide both sides by -1 Method C: -1 -1
flip
flip
1x =
- 4
x = - 4
Divide both sides by -1

14. Usually, we’ll use Method C, because in most problems, the last step is to ______________ both sides by something.

15. 6).
3 = 4 – 2x
+ 4
+ 4
-1 = -2x

16. 6).
3 = 4 – 2x
+ 4
+ 4
-1 = -2x -2 -2
flip
flip
0.5 = x
1/2 = 0.5
Since + 4 is the same as – 4, you could also just write – 4 on both sides.

17. Licensing information
This material is licensed under the Creative Commons Attribution 3.0 license:
Author: Kevin Hall