Simplifying Algebra

Question 1:

x+x+x
3x

Question 2:

x+x+x+x
4x

Question 3:

5x3x+x+2x
5x

Question 4:

4x+3x+2x+2x
11x

Question 5:

3xy+4x+5y
7x+4y

Question 6:

2xz3y+2xz+y
4xz-2y