q) is
true, we assume that p is true and use that to show that q must also be true.3. To prove that an if--then statement (p q) is
true, we assume that p is true and use that to show that q must also be true.
Proof Suppose that a - b = rm and b - c = sm for some integers r and s.
We are trying to conclude that a - c = tm for some integer t. To obtain information about a - c, try adding the two equations above.