Math Problem Statement

(3x-1)/(x+2)≤5

Solution

To solve the inequality 3x1x+25\frac{3x-1}{x+2} \leq 5, follow these steps:

Step 1: Move everything to one side of the inequality

Subtract 5 from both sides to set the inequality to zero: 3x1x+250\frac{3x - 1}{x + 2} - 5 \leq 0 Rewrite the right-hand side as a single fraction: 3x1x+25=3x15(x+2)x+2=3x15x10x+2\frac{3x - 1}{x + 2} - 5 = \frac{3x - 1 - 5(x + 2)}{x + 2} = \frac{3x - 1 - 5x - 10}{x + 2} Simplify the numerator: =2x11x+20= \frac{-2x - 11}{x + 2} \leq 0

Step 2: Solve the inequality

Now solve the inequality: 2x11x+20\frac{-2x - 11}{x + 2} \leq 0

The critical points occur where the numerator and denominator are zero:

  • The numerator 2x11=0-2x - 11 = 0 gives x=112x = -\frac{11}{2}.
  • The denominator x+2=0x + 2 = 0 gives x=2x = -2.

Step 3: Test intervals

These critical points divide the real line into intervals. We need to test each interval to determine where the expression is less than or equal to zero:

  1. Interval (,112)(-\infty, -\frac{11}{2}): Choose x=6x = -6, test in the inequality 2x11x+20\frac{-2x - 11}{x + 2} \leq 0. 2(6)116+2=12114=14<0\frac{-2(-6) - 11}{-6 + 2} = \frac{12 - 11}{-4} = \frac{1}{-4} < 0 This interval satisfies the inequality.

  2. Interval (112,2)(- \frac{11}{2}, -2): Choose x=3x = -3, test in the inequality: 2(3)113+2=6111=51>0\frac{-2(-3) - 11}{-3 + 2} = \frac{6 - 11}{-1} = \frac{-5}{-1} > 0 This interval does not satisfy the inequality.

  3. Interval (2,)(-2, \infty): Choose x=0x = 0, test in the inequality: 2(0)110+2=112<0\frac{-2(0) - 11}{0 + 2} = \frac{-11}{2} < 0 This interval satisfies the inequality.

Step 4: Include or exclude critical points

  • At x=112x = -\frac{11}{2}, 2x11x+2=0\frac{-2x - 11}{x + 2} = 0, so it satisfies the inequality.
  • At x=2x = -2, the denominator is zero, making the expression undefined.

Final Solution:

The solution is: x(,2)[112,)x \in (-\infty, -2) \cup \left[-\frac{11}{2}, \infty\right)

Would you like more details or explanations?

Here are 5 related questions:

  1. How do you solve rational inequalities involving higher-degree polynomials?
  2. What is the process for solving compound inequalities?
  3. How do you graph the solution set for a rational inequality?
  4. Can you explain why the expression is undefined at certain points?
  5. What is the difference between solving equations and inequalities?

Tip: Always check for critical points where the denominator equals zero in rational inequalities!

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Inequalities
Critical Points

Formulas

Rational inequality: (a(x) / b(x)) ≤ c
Critical points: where numerator and denominator are zero

Theorems

Zero of a function
Interval testing for inequalities

Suitable Grade Level

Grades 9-11