1. (6r + 7) + (13 + 7r)
1(6r + 7) + 1(13 + 7r)
6r + 7 + 13 + 7r
13r + 20
2. (13 - 3/2r) - (1 - r )
1(13 - 3/2r) - 1(1 - r )
13 - 3/2r - 1 + r
12 - (3/2r - 2/2r)
12 - 1/2r
3. (-8 - r) + (2r - 4)
1(-8 - r) + 1(2r - 4)
-8 - r + 2r - 4
-12 + r
4. (7r - 3/2) - (2/3 + 6r)
1(7r - 3/2) - 1(2/3 + 6r)
7r - 3/2 - 2/3 - 6r
r + (- 3/2 - 2/3)
r +(- 9 - 4 / 6)
r + -13/6
r - 13/6
Hope this helps!
