Answer
$\frac{2n-6}{n(n-1)}$
Work Step by Step
First, we find the least common multiple of the denominators of the fractions. This, upon inspection, is found to be $n(n-1)$. Then, we use the least common multiple to create a common denominator, allowing us to subtract the fractions:
$\frac{6}{n}-\frac{4}{n-1}$
=$\frac{6(n-1)-4(n)}{n(n-1)}$
=$\frac{6n-6-4n}{n(n-1)}$
=$\frac{6n-4n-6}{n(n-1)}$
=$\frac{2n-6}{n(n-1)}$
