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Zorluk: OrtaLinear and Quadratic Inequalities

Find the set of real values of xx that satisfies both inequalities x2−3x−10<0x^2 - 3x - 10 < 0 and 3−2x≤13 - 2x \le 1.

  1. 1≤x<51 \le x < 5Cevap
  2. B
    −2<x≤1-2 < x \le 1
  3. C
    x<−2 or x>5x < -2 \text{ or } x > 5
  4. D
    −2<x<5-2 < x < 5

Cevap

The set of real values satisfying both inequalities is 1≤x<51 \le x < 5.
Solving the quadratic inequality x2−3x−10<0x^2 - 3x - 10 < 0 gives the open interval −2<x<5-2 < x < 5. Solving the linear inequality 3−2x≤13 - 2x \le 1 gives −2x≤−2-2x \le -2, which upon dividing by −2-2 and reversing the inequality sign becomes x≥1x \ge 1. Finding the overlapping values that satisfy both inequalities gives 1≤x<51 \le x < 5.

Adım Adım Çözüm

1
Solve the quadratic inequality x2−3x−10<0x^2 - 3x - 10 < 0.
Factor into (x−5)(x+2)<0(x - 5)(x + 2) < 0. Critical values are x=−2x = -2 and x=5x = 5. Since the inequality is strictly less than zero, the solution region is −2<x<5-2 < x < 5.
The quadratic expression is negative between its real roots.
2
Solve the linear inequality 3−2x≤13 - 2x \le 1.
Subtract 3 from both sides: −2x≤−2-2x \le -2. Divide by −2-2 and flip the inequality sign: x≥1x \ge 1.
Dividing or multiplying an inequality by a negative number reverses the direction of the inequality sign.
3
Find the intersection of the two solution sets.
Combine −2<x<5-2 < x < 5 and x≥1x \ge 1 to get 1≤x<51 \le x < 5.
Values of xx must satisfy both conditions simultaneously.

Anahtar Kavram

Solving simultaneous linear and quadratic inequalities
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