1. **Problem (i) Part 1:** Find the range of values of $x$ for which $$\frac{2x+1}{x-2} < 1.$$
**Step 1:** Start with the inequality: $$\frac{2x+1}{x-2} < 1.$$
**Step 2:** Bring all terms to one side: $$\frac{2x+1}{x-2} - 1 < 0.$$
**Step 3:** Write with common denominator: $$\frac{2x+1 - (x-2)}{x-2} < 0.$$
Simplify numerator: $$\frac{2x+1 - x + 2}{x-2} = \frac{x + 3}{x-2} < 0.$$
**Step 4:** The inequality $$\frac{x+3}{x-2} < 0$$ holds when numerator and denominator have opposite signs.
- Numerator $x+3 < 0 \Rightarrow x < -3$ (M1)
- Denominator $x-2 > 0 \Rightarrow x > 2$ or $x-2 < 0 \Rightarrow x < 2$ (A1)
**Step 5:** Combine signs:
- If numerator negative ($x < -3$) and denominator positive ($x > 2$) no overlap.
- If numerator positive ($x > -3$) and denominator negative ($x < 2$), then $-3 < x < 2$.
**Step 6:** Check intervals:
- For $x < -3$, numerator negative, denominator negative ($x-2 < 0$), so fraction positive, not less than zero.
- For $-3 < x < 2$, numerator positive, denominator negative, fraction negative, satisfies inequality.
- For $x > 2$, numerator positive, denominator positive, fraction positive, no.
**Step 7:** Exclude $x=2$ (denominator zero).
**Answer:** $$\boxed{-3 < x < 2}.$$
2. **Problem (i) Part 2:** Solve $$\left|\frac{x+1}{2x-3}\right| \leq \frac{x+1}{2x-3}.$$
**Step 1:** Recall that for any real number $a$, $|a| \leq a$ implies $a \geq 0$.
**Step 2:** Set $$a = \frac{x+1}{2x-3}.$$
Inequality becomes $$|a| \leq a \Rightarrow a \geq 0.$$
**Step 3:** Solve $$\frac{x+1}{2x-3} \geq 0.$$
**Step 4:** Find critical points where numerator or denominator is zero:
- Numerator zero at $x = -1$.
- Denominator zero at $x = \frac{3}{2}$.
**Step 5:** Test intervals determined by $-1$ and $\frac{3}{2}$:
- For $x < -1$, numerator negative, denominator negative (since $2x-3 < 0$), fraction positive.
- For $-1 < x < \frac{3}{2}$, numerator positive, denominator negative, fraction negative.
- For $x > \frac{3}{2}$, numerator positive, denominator positive, fraction positive.
**Step 6:** Inequality holds where fraction $\geq 0$:
- $x < -1$ or $x > \frac{3}{2}$.
**Step 7:** Exclude $x = \frac{3}{2}$ (denominator zero).
**Answer:** $$\boxed{x < -1 \text{ or } x > \frac{3}{2}}.$$
3. **Problem (ii):** Find real $x$ such that $$e^{3x} - 3e^x - 4e^{-x} = 0,$$ leaving answer in terms of natural logarithms.
**Step 1:** Let $$y = e^x > 0.$$
Rewrite equation:
$$y^3 - 3y - 4y^{-1} = 0.$$
Multiply both sides by $y$ to clear denominator:
$$y^4 - 3y^2 - 4 = 0.$$
**Step 2:** Let $$z = y^2 > 0.$$
Equation becomes:
$$z^2 - 3z - 4 = 0.$$
**Step 3:** Solve quadratic:
$$z = \frac{3 \pm \sqrt{9 + 16}}{2} = \frac{3 \pm 5}{2}.$$
**Step 4:** Possible values:
- $$z = \frac{3 + 5}{2} = 4,$$
- $$z = \frac{3 - 5}{2} = -1$$ (discard negative since $z = y^2 > 0$).
**Step 5:** So $$y^2 = 4 \Rightarrow y = 2$$ (since $y = e^x > 0$).
**Step 6:** Solve for $x$:
$$e^x = 2 \Rightarrow x = \ln 2.$$
**Answer:** $$\boxed{x = \ln 2}.$$
Inequalities Exponential Fbce5E
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