Question

Difficulty: HardLinear Inequalities and Absolute Value

If xx is a real number that satisfies both 43x>7|4 - 3x| > 7 and 12x33\frac{1 - 2x}{3} \ge -3, which of the following represents the complete set of all possible values of xx?

  1. x<1x < -1 or 113<x5\frac{11}{3} < x \le 5Answer
  2. B
    1<x5-1 < x \le 5
  3. C
    x5x \ge 5
  4. D
    1<x<113-1 < x < \frac{11}{3}
  5. E
    x<1x < -1 or x>113x > \frac{11}{3}

Answer

x<1x < -1 or 113<x5\frac{11}{3} < x \le 5
The correct option correctly solves 43x>7|4 - 3x| > 7 to yield x<1x < -1 or x>113x > \frac{11}{3}, solves 12x33\frac{1 - 2x}{3} \ge -3 to yield x5x \le 5, and takes their intersection to produce x<1x < -1 or 113<x5\frac{11}{3} < x \le 5.

Step-by-Step Solution

1
Solve the absolute value inequality 43x>7|4 - 3x| > 7.
43x>74 - 3x > 7 or 43x<74 - 3x < -7. Solving 43x>74 - 3x > 7 gives 3x>3    x<1-3x > 3 \implies x < -1. Solving 43x<74 - 3x < -7 gives 3x<11    x>113-3x < -11 \implies x > \frac{11}{3}. Thus, x(,1)(113,)x \in (-\infty, -1) \cup (\frac{11}{3}, \infty).
An absolute value inequality of the form u>c|u| > c splits into u>cu > c or u<cu < -c. Dividing by a negative number reverses the inequality direction.
2
Solve the linear inequality 12x33\frac{1 - 2x}{3} \ge -3.
Multiply both sides by 33: 12x91 - 2x \ge -9. Subtract 11: 2x10-2x \ge -10. Divide by 2-2 and flip the inequality sign: x5x \le 5.
Isolating the variable xx requires reversing the inequality sign when dividing by the negative constant 2-2.
3
Find the intersection of the solution sets from Step 1 and Step 2.
We require xx to satisfy (x<1 or x>113)(x < -1 \text{ or } x > \frac{11}{3}) AND x5x \le 5. Case 1: x<1x < -1 automatically satisfies x5x \le 5, giving x<1x < -1. Case 2: x>113x > \frac{11}{3} combined with x5x \le 5 gives 113<x5\frac{11}{3} < x \le 5. Combining both cases yields x<1 or 113<x5x < -1 \text{ or } \frac{11}{3} < x \le 5.
The word 'both' in the stem indicates a logical AND (intersection) between the two conditions.

Key Concept

Solving systems involving absolute value inequalities and linear inequalities requires handling disjunctions (OR) for absolute values greater than a positive constant, reversing inequality signs when multiplying or dividing by negative numbers, and taking the intersection (AND) of all valid regions.
Estimated Time:2m 15s
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