1. Problem: Find the solution set of the equation \( \frac{x}{p(x)} - \frac{x}{r(x)} - 1 = 0 \) where \( p(x) = x - 4 \), \( r(x) = x^2 - 2x - 8 \).
2. Step 1: Write the equation explicitly:
$$\frac{x}{x-4} - \frac{x}{x^2 - 2x - 8} - 1 = 0$$
3. Step 2: Factorize the denominator \( r(x) \):
$$x^2 - 2x - 8 = (x - 4)(x + 2)$$
4. Step 3: Find common denominator \( (x-4)(x+2) \) and rewrite the equation:
$$\frac{x(x+2)}{(x-4)(x+2)} - \frac{x}{(x-4)(x+2)} - 1 = 0$$
5. Step 4: Combine the fractions:
$$\frac{x(x+2) - x}{(x-4)(x+2)} - 1 = 0$$
Simplify numerator:
$$x(x+2) - x = x^2 + 2x - x = x^2 + x$$
6. Step 5: Write the equation as:
$$\frac{x^2 + x}{(x-4)(x+2)} = 1$$
7. Step 6: Multiply both sides by denominator:
$$x^2 + x = (x-4)(x+2)$$
8. Step 7: Expand right side:
$$(x-4)(x+2) = x^2 + 2x - 4x - 8 = x^2 - 2x - 8$$
9. Step 8: Set equation:
$$x^2 + x = x^2 - 2x - 8$$
Subtract \( x^2 \) from both sides:
$$x = -2x - 8$$
10. Step 9: Solve for \( x \):
$$x + 2x = -8$$
$$3x = -8$$
$$x = -\frac{8}{3}$$
11. Step 10: Check for restrictions: denominators cannot be zero.
\( x-4 \neq 0 \Rightarrow x \neq 4 \)
\( x+2 \neq 0 \Rightarrow x \neq -2 \)
Since \( x = -\frac{8}{3} \) is allowed, it is a valid solution.
Final answer: The solution set is \( \left\{ -\frac{8}{3} \right\} \).
Rational Equation Solution
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