1. **Problem 1:** Identify if the expression $\frac{2x+3}{x-1}$ is a rational function, rational equation, or rational inequality.
A rational function is a ratio of two polynomials.
Since $\frac{2x+3}{x-1}$ is a ratio of polynomials, it is a rational function.
2. **Problem 2:** Solve the rational equation $\frac{1}{x} + 2 = 5$.
Step 1: Isolate the fraction: $\frac{1}{x} = 3$.
Step 2: Multiply both sides by $x$: $1 = 3x$.
Step 3: Solve for $x$: $x = \frac{1}{3}$.
3. **Problem 3:** Solve the rational inequality $\frac{x-2}{x+1} > 0$.
Step 1: Find critical points where numerator or denominator is zero: $x=2$ and $x=-1$.
Step 2: Test intervals: $(-\infty,-1)$, $(-1,2)$, $(2,\infty)$.
Step 3: Check signs:
- For $x=-2$: $\frac{-2-2}{-2+1} = \frac{-4}{-1} = 4 > 0$ (True)
- For $x=0$: $\frac{0-2}{0+1} = \frac{-2}{1} = -2 < 0$ (False)
- For $x=3$: $\frac{3-2}{3+1} = \frac{1}{4} > 0$ (True)
Step 4: Solution: $(-\infty,-1) \cup (2,\infty)$ excluding $x=-1$ where denominator is zero.
4. **Problem 4:** Simplify the rational expression $\frac{x^2-9}{x^2-6x+9}$.
Step 1: Factor numerator and denominator:
- Numerator: $x^2-9 = (x-3)(x+3)$
- Denominator: $x^2-6x+9 = (x-3)^2$
Step 2: Cancel common factor $(x-3)$:
Result: $\frac{x+3}{x-3}$, with $x \neq 3$.
5. **Problem 5:** Solve the rational equation $\frac{2}{x+1} = \frac{3}{x-2}$.
Step 1: Cross multiply:
$2(x-2) = 3(x+1)$
Step 2: Expand:
$2x - 4 = 3x + 3$
Step 3: Rearrange:
$-4 - 3 = 3x - 2x$
$-7 = x$
Step 4: Check restrictions: $x \neq -1, 2$; $x=-7$ is valid.
6. **Problem 6:** Determine the domain of $f(x) = \frac{5}{x^2 - 4}$.
Step 1: Set denominator not equal to zero:
$x^2 - 4 \neq 0$
Step 2: Factor:
$(x-2)(x+2) \neq 0$
Step 3: Domain is all real numbers except $x=2$ and $x=-2$.
7. **Problem 7:** Solve the rational inequality $\frac{3x}{x-5} \leq 6$.
Step 1: Bring all terms to one side:
$\frac{3x}{x-5} - 6 \leq 0$
Step 2: Write as single fraction:
$\frac{3x - 6(x-5)}{x-5} \leq 0$
Step 3: Simplify numerator:
$3x - 6x + 30 = -3x + 30$
Step 4: Inequality:
$\frac{-3x + 30}{x-5} \leq 0$
Step 5: Critical points: numerator zero at $x=10$, denominator zero at $x=5$.
Step 6: Test intervals:
- $(-\infty,5)$: pick $x=0$, fraction $\frac{30}{-5} = -6 \leq 0$ True
- $(5,10)$: pick $x=6$, fraction $\frac{-18+30}{1} = 12 > 0$ False
- $(10,\infty)$: pick $x=11$, fraction $\frac{-33+30}{6} = -3/6 = -0.5 \leq 0$ True
Step 7: Solution: $(-\infty,5) \cup [10,\infty)$ excluding $x=5$ where denominator zero.
8. **Problem 8:** Simplify $\frac{4x^2 - 1}{2x - 1}$.
Step 1: Factor numerator:
$4x^2 - 1 = (2x - 1)(2x + 1)$
Step 2: Cancel common factor:
Result: $2x + 1$, with $x \neq \frac{1}{2}$.
9. **Problem 9:** Solve the rational equation $\frac{1}{x+2} + \frac{2}{x-1} = 0$.
Step 1: Find common denominator: $(x+2)(x-1)$.
Step 2: Multiply both sides by denominator:
$(x-1) + 2(x+2) = 0$
Step 3: Expand:
$x - 1 + 2x + 4 = 0$
Step 4: Combine like terms:
$3x + 3 = 0$
Step 5: Solve for $x$:
$3x = -3$ so $x = -1$
Step 6: Check restrictions: $x \neq -2, 1$; $x=-1$ valid.
10. **Problem 10:** Determine if $\frac{x^2 + x - 6}{x^2 - 4}$ is defined at $x=2$.
Step 1: Factor denominator:
$x^2 - 4 = (x-2)(x+2)$
Step 2: At $x=2$, denominator is zero, so expression is undefined.
**Answer Key:**
1. Rational function
2. $x=\frac{1}{3}$
3. $(-\infty,-1) \cup (2,\infty)$
4. $\frac{x+3}{x-3}$
5. $x=-7$
6. Domain: $x \neq \pm 2$
7. $(-\infty,5) \cup [10,\infty)$, $x \neq 5$
8. $2x + 1$
9. $x=-1$
10. Undefined at $x=2$
Rational Functions 02D685
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