Math Problem Statement

(x + 1)/(x + 3) <= 2

Solution

To solve the inequality x+1x+32\frac{x + 1}{x + 3} \leq 2, we need to consider the following steps:

Step 1: Move all terms to one side

First, subtract 22 from both sides to bring all terms to one side of the inequality:

x+1x+320\frac{x + 1}{x + 3} - 2 \leq 0

Step 2: Combine the fractions

To combine the fractions, express 22 as 2(x+3)x+3\frac{2(x + 3)}{x + 3}:

x+12(x+3)x+30\frac{x + 1 - 2(x + 3)}{x + 3} \leq 0

Simplify the numerator:

x+12x6x+30\frac{x + 1 - 2x - 6}{x + 3} \leq 0

x5x+30\frac{-x - 5}{x + 3} \leq 0

Step 3: Analyze the inequality

Now, we need to determine when the fraction x5x+3\frac{-x - 5}{x + 3} is less than or equal to zero.

The fraction is equal to zero when the numerator x5=0-x - 5 = 0, so:

x5=0    x=5-x - 5 = 0 \implies x = -5

Next, we check the sign of the fraction in different intervals determined by the critical points x=5x = -5 and x=3x = -3 (where the denominator x+3=0x + 3 = 0).

Step 4: Test intervals

The intervals to test are:

  1. x<5x < -5
  2. 5<x<3-5 < x < -3
  3. x>3x > -3
  • For x<5x < -5, both x5-x - 5 and x+3x + 3 are negative, so the fraction is positive.
  • For 5<x<3-5 < x < -3, x5-x - 5 is negative and x+3x + 3 is positive, so the fraction is negative.
  • For x>3x > -3, both x5-x - 5 and x+3x + 3 are positive, so the fraction is negative.

Step 5: Solution

The inequality is satisfied when the fraction is less than or equal to zero:

5x<3-5 \leq x < -3

Thus, the solution to the inequality is:

x[5,3)x \in [-5, -3)

Do you have any questions, or would you like more details on any step?

Here are 5 related questions to consider:

  1. How would the solution change if the inequality were strict x+1x+3<2\frac{x + 1}{x + 3} < 2?
  2. How do you solve the inequality if the expression is x1x+31\frac{x - 1}{x + 3} \leq -1?
  3. What are the critical points for the function x+1x+3\frac{x + 1}{x + 3}?
  4. How can the sign chart method help in solving inequalities like this?
  5. What would happen if the denominator x+3x + 3 was a squared term?

Tip: Always check the sign of both the numerator and denominator separately when solving inequalities involving fractions. This helps determine the intervals where the inequality holds.

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Math Problem Analysis

Mathematical Concepts

Algebra
Inequalities
Rational Functions

Formulas

Fractional Inequalities
Combining Fractions

Theorems

Sign Analysis Method
Critical Points in Rational Inequalities

Suitable Grade Level

Grades 10-12