1. Counterexamples

2. Conjecture:
The perimeter of a rectangle can never be an odd
number

3. Counterexample :
- an example that shows a general statement
to be false.
- it only takes one counterexample to prove
a conjecture false

4. Conjecture:
Every rectangle is a square.
Counterexample:

5. Conjecture:
If a>b and b=5, then a ≥ 6
Counterexample:

6. Students with low grade-point averages in high
school are invariably failures in life.

7. Exercise 48
Omit question 9