1. p[0] = 21/45, p[1] = 21/45, p[2] = 3/45.
2. 20 cents.
3. $18.
4. 13.86
5. 1.894
6. about 0.004
7. about 795.
8. x = -1/2, y = 4.
9. x = 1/2, y = 3, z = -1.
10. x = 12 - 13z, y = 3 - 2z, z = any number.
11. matrix row 1: 2, 1, 5; row 2: -4, 3, 1; row 3: -1, -2,
2.
12. matrix row 1: -3, 0; row 2: -6, -9.
13. matrix row 1: 1, 2, 10; row 2: -12, 0, 3; row 3: 1, -4,
-2.
14. matrix row 1: 1, 2; row 2: 0, 3.
15. matrix row 1: 0, 0, 1/4; row 2: 0, -1/2, 0; row 3: 1/3,
0, -1/12.
