1. (a) (3, 1) (b) (3, 1) (c) (1, 6)
2. (a) (3, 1) (b) (8, 3) (c) (5, -2)
3. (a) (3, 1) (b) (3, 1) (c) (9, 3)
4. (a) (1, 3) (b) (4, 1) (c) (2, -2)
5. (a) (3, ) (b) (5, -1) (c) (-1, -3)
6. (a) 1 pie costs $2 (b) 1 milkshake costs $2
7. (a) $8 (b) $3