Math Problem Statement

Solve the rational inequality: (x - 2) / (x - 4) > 0.

Solution

The problem shown in the image is the rational inequality:

x2x4>0\frac{x - 2}{x - 4} > 0

Steps to solve the inequality:

  1. Identify the critical points: These are the values of xx that make either the numerator or the denominator zero.

    • From the numerator x2=0x - 2 = 0, we get x=2x = 2.
    • From the denominator x4=0x - 4 = 0, we get x=4x = 4.
  2. Divide the number line into intervals based on the critical points. The critical points divide the number line into three intervals:

    • (,2)(-\infty, 2)
    • (2,4)(2, 4)
    • (4,)(4, \infty)
  3. Test a value from each interval to determine the sign of the expression x2x4\frac{x - 2}{x - 4} in each interval:

    • For (,2)(-\infty, 2), choose x=0x = 0: 0204=24=12>0\frac{0 - 2}{0 - 4} = \frac{-2}{-4} = \frac{1}{2} > 0 The expression is positive in this interval.
    • For (2,4)(2, 4), choose x=3x = 3: 3234=11=1<0\frac{3 - 2}{3 - 4} = \frac{1}{-1} = -1 < 0 The expression is negative in this interval.
    • For (4,)(4, \infty), choose x=5x = 5: 5254=31=3>0\frac{5 - 2}{5 - 4} = \frac{3}{1} = 3 > 0 The expression is positive in this interval.
  4. Analyze the critical points:

    • At x=2x = 2, the numerator is zero, so x2x4=0\frac{x - 2}{x - 4} = 0.
    • At x=4x = 4, the denominator is zero, so the expression is undefined at this point.
  5. Conclusion:

    • The inequality x2x4>0\frac{x - 2}{x - 4} > 0 holds in the intervals (,2)(-\infty, 2) and (4,)(4, \infty), but not at x=2x = 2 or x=4x = 4.
    • Therefore, the solution is: (,2)(4,)(-\infty, 2) \cup (4, \infty)

Would you like any additional details or have questions about the steps?

Related Questions:

  1. How do we handle rational inequalities that are less than 0?
  2. What changes if the inequality is \geq or \leq instead of strict >>?
  3. How would the solution change if there were different terms in the numerator or denominator?
  4. What would happen if there were more than two critical points?
  5. How do we graph the solution on a number line?

Tip: Always test points from the intervals between critical values to determine where the expression is positive or negative.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Inequalities
Number Line Analysis

Formulas

Test values from intervals between critical points
Inequalities
Zero Product Property

Theorems

Sign Testing Method for Rational Inequalities

Suitable Grade Level

Grades 9-10