Simplify each expression. If not possible, write simplified.

1. 12a - a

2. 3x + 6x

3. 3x - 1

1). You have 12 of something, and 1 of the same thing is taken away.

How many of it do you have then?

2). You have 3 of something, and 6 more come along.

How many of it do you have then?

3). Simplified.

1. 12-1 = 11 11a

2. 3+6 = 9 9x

3. 3x-1 (already simplified - not 'like' terms)