Math Problem Statement

1) Solve the inequality (2x - 8) / (x - 2) >= 0 2) Solve the equation x / (x - 2) - 7 = 2 / (x - 2)

Solution

Let's go through each problem you have on the sheet.

Problem 1:

2x8x20\frac{2x - 8}{x - 2} \geq 0

This is an inequality involving a rational function. To solve this, we need to analyze the numerator and denominator.

  1. Simplify the expression:
    The numerator 2x82x - 8 can be factored as: 2(x4)2(x - 4) So, the inequality becomes: 2(x4)x20\frac{2(x - 4)}{x - 2} \geq 0

  2. Find critical points:
    The expression equals 0 when the numerator is 0, i.e., x=4x = 4.
    The expression is undefined when the denominator is 0, i.e., x=2x = 2.

  3. Test intervals:
    The critical points divide the number line into three intervals: (,2)(-\infty, 2), (2,4)(2, 4), and (4,)(4, \infty). We will test the sign of the expression in each interval.

    • For x<2x < 2, choose x=0x = 0: 2(04)02=82=4(positive)\frac{2(0 - 4)}{0 - 2} = \frac{-8}{-2} = 4 \quad (\text{positive})
    • For 2<x<42 < x < 4, choose x=3x = 3: 2(34)32=21=2(negative)\frac{2(3 - 4)}{3 - 2} = \frac{-2}{1} = -2 \quad (\text{negative})
    • For x>4x > 4, choose x=5x = 5: 2(54)52=23(positive)\frac{2(5 - 4)}{5 - 2} = \frac{2}{3} \quad (\text{positive})
  4. Conclusion:
    The inequality is satisfied where the expression is positive or zero. Therefore, the solution is: (,2)[4,)(-\infty, 2) \cup [4, \infty) x=2x = 2 is excluded because the denominator becomes zero there, but x=4x = 4 is included because it makes the numerator zero.


Problem 2:

xx27=2x2\frac{x}{x - 2} - 7 = \frac{2}{x - 2}

This is an equation involving fractions with the same denominator. To solve:

  1. Rewrite the equation: xx27=2x2\frac{x}{x - 2} - 7 = \frac{2}{x - 2}

  2. Combine terms with the same denominator:
    First, bring both fractions on the left-hand side together: x2x27=0\frac{x - 2}{x - 2} - 7 = 0 Add both sides to simplify the equation further and solve

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Math Problem Analysis

Mathematical Concepts

Inequalities
Rational Equations
Factoring

Formulas

Inequality solution steps: Find critical points and test intervals
Rational equation solving: Combine terms with common denominators

Theorems

Sign analysis for rational inequalities
Equation solving for rational terms with common denominators

Suitable Grade Level

Grade 10-12