This shows that the statement is true for these examples, but to prove that it is true all the time we must use algebra. Write the first of the two even numbers as \(2n\), where \(n\) is an integer.

Following the methods of Serret, Jordan and Netto, the authors give just so much of the elementary theory of substitution-groups as to enable them to prove ... equations which do admit of ...

This shows that the statement is true for these examples, but to prove that it is true all the time we can use algebra. Write the first of the two even numbers as \(2n\), where \(n\) is an integer.