Math HW3

Requested by Chester

Prove the following theorems using two columns

1. Theorem 2-11 - The cancellation law for multiplication
For any numbers a and b and any nonzero number c, if a•c = b•c, then a = b

2. Theorem 2-12
If a and c are numbers such that a•c = 0, then either a = 0 or c = 0

3. Theorem 2-13
If a and b are nonzero numbers, then 1/(a•b) = (1/a)•(1/b)

4. Theorem 4-3
If a is a positive real number, then -a is negative, and if a is negative then -a is positive.

5. Theorem 4-7
If a, b, and c are in R and a > b and 0 > c, then b•c > a•c

6. Theorem 4-8
If a > 0, then 1/a > 0

*yawn*