15 (3)/(n-4)+(3)/(5n-6) (9)/((n-4)(5n-6)) (18a-30)/((n-4)(5a-6)) D (12)/((n-4)(5n-6)) (3)/(3x-5) Simplify. D A B C

## Step 1: Identify the fractions to be simplified<br />### The problem involves simplifying the fractions \( \frac{3}{n-4} \) and \( \frac{3}{5-6} \).<br /><br />## Step 2: Simplify the second fraction<br />### The fraction \( \frac{3}{5-6} \) simplifies to \( \frac{3}{-1} \), which is \( -3 \).<br /><br />## Step 3: Substitute the simplified fraction into the first fraction<br />### Substitute \( -3 \) into the first fraction, we get \( \frac{3}{n-4} \times -3 \).<br /><br />## Step 4: Simplify the expression<br />### Simplify the expression to get \( \frac{-9}{n-4} \).<br /><br />## Step 5: Compare with the given options<br />### Compare the simplified expression with the given options. The correct option is the one that matches the simplified expression.