3. Solve and check:
4. Solve (after looking up the special short method):
5. Solve by the special short method:
6. At what time between 8 and 9 o'clock are the hands of a watch (a) opposite each other? (b) at right angles? (c) together?
Work out (a) and state the equations for (b) and (c).
7. The formula for converting a temperature of F degrees Fahrenheit into its equivalent temperature of C degrees Centigrade is