Question: Subtract.
$\frac{x}{2x - 3} - \frac{x + 6}{3x}$
Simplify your answer as much as possible.
1. **State the problem:** We need to subtract the two rational expressions:
$$\frac{x}{2x - 3} - \frac{x + 6}{3x}$$
2. **Find a common denominator:** The denominators are $2x - 3$ and $3x$. The least common denominator (LCD) is:
$$\text{LCD} = (2x - 3)(3x)$$
3. **Rewrite each fraction with the LCD:**
$$\frac{x}{2x - 3} = \frac{x \cdot 3x}{(2x - 3)(3x)} = \frac{3x^2}{(2x - 3)(3x)}$$
$$\frac{x + 6}{3x} = \frac{(x + 6)(2x - 3)}{(3x)(2x - 3)}$$
4. **Subtract the numerators over the common denominator:**
$$\frac{3x^2 - (x + 6)(2x - 3)}{(2x - 3)(3x)}$$
5. **Expand the numerator:**
First expand $(x + 6)(2x - 3)$:
$$x \cdot 2x = 2x^2$$
$$x \cdot (-3) = -3x$$
$$6 \cdot 2x = 12x$$
$$6 \cdot (-3) = -18$$
So,
$$(x + 6)(2x - 3) = 2x^2 - 3x + 12x - 18 = 2x^2 + 9x - 18$$
6. **Substitute back and simplify numerator:**
$$3x^2 - (2x^2 + 9x - 18) = 3x^2 - 2x^2 - 9x + 18 = x^2 - 9x + 18$$
7. **Factor the numerator if possible:**
$$x^2 - 9x + 18$$
Factors of 18 that sum to -9 are -6 and -3, so:
$$x^2 - 9x + 18 = (x - 6)(x - 3)$$
8. **Write the final expression:**
$$\frac{(x - 6)(x - 3)}{(2x - 3)(3x)}$$
This is the simplified form since numerator and denominator have no common factors.
**Final answer:**
$$\frac{(x - 6)(x - 3)}{3x(2x - 3)}$$