Math Problem Statement

|(x-3)/(x+6)|>=2

Solution

To solve the inequality:

x3x+62\left| \frac{x - 3}{x + 6} \right| \geq 2

We need to split this into two cases based on the definition of absolute value:

x3x+62orx3x+62\frac{x - 3}{x + 6} \geq 2 \quad \text{or} \quad \frac{x - 3}{x + 6} \leq -2

Case 1: x3x+62\frac{x - 3}{x + 6} \geq 2

  1. Multiply both sides by x+6x + 6, but note that x+6x + 6 could be positive or negative. Therefore, we must consider two subcases:
    • If x+6>0x + 6 > 0 (i.e., x>6x > -6), multiply directly.
    • If x+6<0x + 6 < 0 (i.e., x<6x < -6), reverse the inequality.

Subcase 1.1: x>6x > -6

x3x+62x32(x+6)\frac{x - 3}{x + 6} \geq 2 \quad \Rightarrow \quad x - 3 \geq 2(x + 6) Expanding: x32x+12x - 3 \geq 2x + 12 Simplifying: x2x12+3x15x15x - 2x \geq 12 + 3 \quad \Rightarrow \quad -x \geq 15 \quad \Rightarrow \quad x \leq -15

But since this must hold under the condition x>6x > -6, there is no solution in this case, because x15x \leq -15 contradicts x>6x > -6.

Subcase 1.2: x<6x < -6

Now reverse the inequality: x32(x+6)x - 3 \leq 2(x + 6) Expanding: x32x+12x - 3 \leq 2x + 12 Simplifying: x2x12+3x15x15x - 2x \leq 12 + 3 \quad \Rightarrow \quad -x \leq 15 \quad \Rightarrow \quad x \geq -15 This gives the range 15x<6-15 \leq x < -6.

Case 2: x3x+62\frac{x - 3}{x + 6} \leq -2

Again, multiply both sides by x+6x + 6 and consider two subcases.

Subcase 2.1: x>6x > -6

x3x+62x32(x+6)\frac{x - 3}{x + 6} \leq -2 \quad \Rightarrow \quad x - 3 \leq -2(x + 6) Expanding: x32x12x - 3 \leq -2x - 12 Simplifying: x+2x12+33x9x3x + 2x \leq -12 + 3 \quad \Rightarrow \quad 3x \leq -9 \quad \Rightarrow \quad x \leq -3 Thus, the solution for this subcase is x3x \leq -3, but under the condition x>6x > -6, so the solution is 6<x3-6 < x \leq -3.

Subcase 2.2: x<6x < -6

Reverse the inequality: x32(x+6)x - 3 \geq -2(x + 6) Expanding: x32x12x - 3 \geq -2x - 12 Simplifying: x+2x12+33x9x3x + 2x \geq -12 + 3 \quad \Rightarrow \quad 3x \geq -9 \quad \Rightarrow \quad x \geq -3 But since x<6x < -6, this is a contradiction, so no solution exists in this subcase.

Final Solution:

Combining both cases, the solution is:

15x<6or6<x3-15 \leq x < -6 \quad \text{or} \quad -6 < x \leq -3

Note that x=6x = -6 is excluded because it would make the denominator zero.

Would you like further clarification or more details?


Here are 5 related questions for further practice:

  1. Solve x+2x43\left| \frac{x + 2}{x - 4} \right| \geq 3.
  2. Solve 2x5x+14\left| \frac{2x - 5}{x + 1} \right| \leq 4.
  3. Solve the inequality x1x+3>1\frac{x - 1}{x + 3} > 1.
  4. Solve x+3x7=2\left| \frac{x + 3}{x - 7} \right| = 2.
  5. Solve the quadratic inequality x23x+25\left| x^2 - 3x + 2 \right| \leq 5.

Tip: Always remember to consider the sign of the denominator when dealing with rational inequalities!

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Math Problem Analysis

Mathematical Concepts

Inequalities
Absolute Value
Rational Expressions

Formulas

|a/b| >= c means either a/b >= c or a/b <= -c

Theorems

Properties of absolute values
Rational inequality solving

Suitable Grade Level

Grades 10-12