1. Find the H. C. F.:

2. Solve the following set of equations:

3. Expand and simplify:

4. An automobile goes 80 miles and back in 9 hours. The rate of speed returning was 4 miles per hour faster than the rate going. Find the rate each way.

5. Simplify:

6. Solve for x:

7. A, B, and C, all working together, can do a piece of work in days. A works twice as fast as C, and A and C together could do the work in 4 days. How long would it take each one of the three to do the work alone?