Answer:
These two statements are equivalent because statement A is the contrapositive of statement B.
Step-by-step explanation:
In logic, when we have an "if" statement we can have its contrapositive or its converse.
Given a "if p, then q" (p is the hypothesis and q is the conclusion), the converse is "if q, then p", in other words, we interchange the hypothesis and the conclusion.
Now, given a "if p, then q", the contrapositive is "if not q, then not p". In other words, we take the negation of both the hypothesis and the conclusion and then we interchange them.
Now, let's take a look at our statements:
<em>If a and b are two real numbers, and if ab = 0, then either a = 0 or b = 0.</em>
In this case:
p = a and b are two real numbers and ab=0
q = either a = 0 or b = 0
Now, let's take the negative of p and q:
The negative of p would be: <em>a and b are two real numbers and their product is not zero.</em>
The negative of q would be: <em>neither of the two real numbers is zero</em>
Now, given than the contrapositive is "if not q, then not p" we would have:
If neither of two real numbers is zero, then their product is not zero.
We can see that this last sentence is the contrapositive of the first one and thus:
These two statements are equivalent because statement A is the contrapositive of statement B.
translates to 
