Determine the values of the positive integer $n$ for which $$A =\sqrt{\frac{9n - 1}{n + 7}}$$is rational.
Problem
Source: New Zealand NZMOC Camp Selection Problems 2010 Seniors 5
Tags: number theory, algebra, rational
Source: New Zealand NZMOC Camp Selection Problems 2010 Seniors 5
Tags: number theory, algebra, rational
Determine the values of the positive integer $n$ for which $$A =\sqrt{\frac{9n - 1}{n + 7}}$$is rational.