a means that either b
= a or a + (-b) is positive. 2. Recall from the reading in Section 3.0 that by definition, b a means that either b
= a or a + (-b) is positive.
Restating the question in an if--then form we obtain: If a and b are
negative integers and a | b, then b a.
To prove an if--then statement (p 
q) is true, you can assume that p is true and show that q
must also be true.
Proof Suppose that a and b are negative integers and a | b.
To show that b a, use the definition of divisibility to show that either
b = a or a + (-b) must be positive.