1. **State the problem:** Solve the inequality $$\frac{2x}{x+1} < -2$$ using the Case Analysis Method.
2. **Rewrite the inequality in the form $$\frac{P(x)}{Q(x)} < 0$$:**
Start by moving all terms to the left side:
$$\frac{2x}{x+1} + 2 < 0$$
3. **Combine into a single rational expression:**
Find a common denominator $x+1$:
$$\frac{2x}{x+1} + \frac{2(x+1)}{x+1} < 0$$
Simplify numerator:
$$\frac{2x + 2(x+1)}{x+1} < 0$$
$$\frac{2x + 2x + 2}{x+1} < 0$$
$$\frac{4x + 2}{x+1} < 0$$
So, $$P(x) = 4x + 2$$ and $$Q(x) = x + 1$$.
4. **Find critical points:**
Set numerator and denominator equal to zero:
$$4x + 2 = 0 \Rightarrow x = -\frac{1}{2}$$
$$x + 1 = 0 \Rightarrow x = -1$$
These points divide the number line into intervals:
$$(-\infty, -1), (-1, -\frac{1}{2}), (-\frac{1}{2}, \infty)$$
5. **Analyze the sign of $$\frac{4x+2}{x+1}$$ on each interval:**
- For $$x < -1$$, pick $$x = -2$$:
$$P(-2) = 4(-2) + 2 = -8 + 2 = -6 < 0$$
$$Q(-2) = -2 + 1 = -1 < 0$$
Fraction sign: $$\frac{negative}{negative} = positive$$ (not less than zero)
- For $$-1 < x < -\frac{1}{2}$$, pick $$x = -0.75$$:
$$P(-0.75) = 4(-0.75) + 2 = -3 + 2 = -1 < 0$$
$$Q(-0.75) = -0.75 + 1 = 0.25 > 0$$
Fraction sign: $$\frac{negative}{positive} = negative$$ (less than zero, solution interval)
- For $$x > -\frac{1}{2}$$, pick $$x = 0$$:
$$P(0) = 2 > 0$$
$$Q(0) = 1 > 0$$
Fraction sign: $$\frac{positive}{positive} = positive$$ (not less than zero)
6. **Check points where denominator is zero:**
At $$x = -1$$, denominator zero, so $$x = -1$$ is excluded.
At $$x = -\frac{1}{2}$$, numerator zero, fraction equals zero, but inequality is strict $$< 0$$, so exclude $$x = -\frac{1}{2}$$.
7. **Write the solution in set builder notation:**
$$\{ x \mid -1 < x < -\frac{1}{2} \}$$
**Final answer:** $$\boxed{\{ x \mid -1 < x < -\frac{1}{2} \}}$$
Rational Inequality 48B5A7
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.