3)Milo proposed the following conjecture:
If a, b, c, and d are any real numbers such that a < b and c < d, then ac < bd.

a) Give two examples for which the conjecture is true and one counterexample.

b) For what set of numbers is the conjecture true?

4. Show that the absolute value of the difference between the squares of consecutive whole numbers is equal to the sum of the two numbers.