1. The problem statement, all variables and given/known data Prove that there is at most one real number b with the property that br=r for all real numbers r. (Such a number is called a multiplicative identity) Note: to show there is a unique object with a certain property, show that (1) there is an object with the property and (2) if objects A and B have the property, then A=B. 2. Relevant equations It looks like the statement is false. 3. The attempt at a solution Let r=0, then b(0)=(0). b can then equal anything because anything times 0 is 0, so when r=0, there is more than one real number b with the property that br=r. The statement is false. Am I right, or is this problem really a lot harder than that?