Math Problem Statement

Solve the following inequalities: 1. 1/(x+1) < 2/(3x-1) 2. (x+2)/(x+4) < (x-1)/(x-2)

Solution

The uploaded image contains two inequalities:

6) 1x+1<23x1\frac{1}{x+1} < \frac{2}{3x-1}

7) x+2x+4<x1x2\frac{x+2}{x+4} < \frac{x-1}{x-2}

Let's solve both inequalities one by one.


Problem 6:

1x+1<23x1\frac{1}{x+1} < \frac{2}{3x-1}

To solve this, follow these steps:

  1. Cross-multiply the terms, but be careful with signs of x+1x+1 and 3x13x-1. This is valid as long as both sides have the same sign, which we must account for later: 1(3x1)<2(x+1)1(3x-1) < 2(x+1) Expanding both sides: 3x1<2x+23x - 1 < 2x + 2

  2. Simplify the inequality: 3x2x<2+13x - 2x < 2 + 1 x<3x < 3

  3. Now consider the restrictions on the domain of the inequality. Both x+1x+1 and 3x13x-1 must be nonzero (otherwise, division by zero occurs):

    • x+10x1x + 1 \neq 0 \Rightarrow x \neq -1
    • 3x10x133x - 1 \neq 0 \Rightarrow x \neq \frac{1}{3}

Thus, the solution is: x<3andx1,13x < 3 \quad \text{and} \quad x \neq -1, \frac{1}{3}


Problem 7:

x+2x+4<x1x2\frac{x+2}{x+4} < \frac{x-1}{x-2}

Again, let's solve this step by step:

  1. Cross-multiply the terms (considering the signs of x+4x+4 and x2x-2): (x+2)(x2)<(x1)(x+4)(x+2)(x-2) < (x-1)(x+4) Use the distributive property to expand both sides: (x24)<(x2+3x4)(x^2 - 4) < (x^2 + 3x - 4)

  2. Simplify the inequality: x24<x2+3x4x^2 - 4 < x^2 + 3x - 4 Cancel out the x2x^2 terms: 4<3x4-4 < 3x - 4 Add 4 to both sides: 0<3x0 < 3x Divide by 3: 0<xorx>00 < x \quad \text{or} \quad x > 0

  3. Consider the restrictions on the domain:

    • x+40x4x+4 \neq 0 \Rightarrow x \neq -4
    • x20x2x-2 \neq 0 \Rightarrow x \neq 2

Thus, the solution is: x>0andx4,2x > 0 \quad \text{and} \quad x \neq -4, 2


Do you want further details or have any questions?

Here are 5 related questions you might want to explore:

  1. How do we deal with inequalities when cross-multiplying fractions?
  2. What are the steps to solve rational inequalities involving more complex expressions?
  3. How do you determine the domain restrictions when solving rational inequalities?
  4. Can rational inequalities have multiple valid solution intervals?
  5. How would you graph the solution sets for these inequalities?

Tip: Always check for restrictions (like division by zero) when solving rational inequalities to avoid invalid solutions.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Inequalities
Cross-multiplication
Domain Restrictions

Formulas

Cross-multiplication of rational expressions: a/b < c/d implies ad < bc (with sign considerations)
Simplifying linear expressions: a(x) < b(x)

Theorems

Basic Inequality Theorems
Domain Restrictions to avoid division by zero

Suitable Grade Level

Grade 10-12