Math Problem Statement

Solving the Rational Inequality: (x+2)/(x-3) ≥ 0

Solution

To solve the rational inequality:

x+2x30\frac{x+2}{x-3} \geq 0

Steps:

  1. Find critical points: These are values of xx that make the numerator or denominator equal to zero.

    • Set x+2=0x=2x+2 = 0 \Rightarrow x = -2 (numerator).
    • Set x3=0x=3x-3 = 0 \Rightarrow x = 3 (denominator).

    So, the critical points are x=2x = -2 and x=3x = 3. Notice that x=3x = 3 will make the denominator zero, which means the function is undefined at this point.

  2. Create test intervals: Divide the real line based on the critical points:

    • Interval 1: (,2)(-\infty, -2)
    • Interval 2: (2,3)(-2, 3)
    • Interval 3: (3,)(3, \infty)
  3. Test the sign in each interval: Pick a test point from each interval and determine whether the expression is positive or negative.

    • For x=3x = -3 (from interval (,2)(-∞, -2)): 3+233=16=16>0\frac{-3+2}{-3-3} = \frac{-1}{-6} = \frac{1}{6} > 0 The expression is positive in this interval.

    • For x=0x = 0 (from interval (2,3)(-2, 3)): 0+203=23=23<0\frac{0+2}{0-3} = \frac{2}{-3} = -\frac{2}{3} < 0 The expression is negative in this interval.

    • For x=4x = 4 (from interval (3,)(3, ∞)): 4+243=61=6>0\frac{4+2}{4-3} = \frac{6}{1} = 6 > 0 The expression is positive in this interval.

  4. Analyze the critical points:

    • At x=2x = -2, the numerator is zero, so x+2x3=0\frac{x+2}{x-3} = 0. This satisfies the inequality because we are looking for 0\geq 0.
    • At x=3x = 3, the denominator is zero, so the expression is undefined. Hence, x=3x = 3 is excluded from the solution.
  5. Conclusion: The solution includes the intervals where the expression is positive or zero: (,2](3,)(-\infty, -2] \cup (3, \infty)

Final answer:

x(,2](3,)x \in (-\infty, -2] \cup (3, \infty)


Would you like more details or have any questions?

Here are 5 related questions:

  1. How do we solve rational inequalities with quadratic expressions?
  2. What happens if both numerator and denominator contain factors?
  3. Can we solve rational inequalities using a sign chart method?
  4. How do we deal with strict inequalities (e.g., >0> 0) in rational functions?
  5. How do we interpret the graph of a rational function with inequality constraints?

Tip: Always check critical points where the expression is undefined by setting the denominator to zero!

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Math Problem Analysis

Mathematical Concepts

Rational Inequalities
Critical Points
Sign Testing

Formulas

(x+2)/(x-3) ≥ 0
Critical Points: Set numerator and denominator equal to zero

Theorems

Critical Point Theorem
Inequality Sign Testing

Suitable Grade Level

Grades 9-12