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

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

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

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

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

What other operations would make something flip?

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

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

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

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

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

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

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

6). 3 = 4 – 2x + 4 + 4 -1 = -2x

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.

Licensing information This material is licensed under the Creative Commons Attribution 3.0 license: http://creativecommons.org/licenses/by/3.0/. Author: Kevin Hall