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Задача Задача №2450314
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Аноним
09 декабря 2024 14:11 · публичный вопрос
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Аноним

(x−3)(2x+7)>0.

Нейросеть09 декабря 2024 14:11

To solve the inequality \((x - 3)(2x + 7) > 0\), we need to find the values of \(x\) for which this product is positive.

Step 1: Determine the critical points.

Set each factor equal to zero:

  1. \(x - 3 = 0 \Rightarrow x = 3\)
  2. \(2x + 7 = 0 \Rightarrow 2x = -7 \Rightarrow x = -\frac{7}{2}\)

The critical points are \(x = 3\) and \(x = -\frac{7}{2}\).

Step 2: Test the intervals determined by these critical points.

The critical points divide the number line into three intervals:

  • \( (-\infty, -\frac{7}{2}) \)
  • \( (-\frac{7}{2}, 3) \)
  • \( (3, \infty) \)

Step 3: Test a point from each interval.

  1. For the interval \( (-\infty, -\frac{7}{2}) \), let’s choose \(x = -4\): \[ (-4 - 3)(2(-4) + 7) = (-7)(-8 + 7) = (-7)(-1) = 7 > 0 \] (The product is positive.)

  2. For the interval \( (-\frac{7}{2}, 3) \), let’s choose \(x = 0\): \[ (0 - 3)(2(0) + 7) = (-3)(7) = -21 < 0 \] (The product is negative.)

  3. For the interval \( (3, \infty) \), let’s choose \(x = 4\): \[ (4 - 3)(2(4) + 7) = (1)(8 + 7) = (1)(15) = 15 > 0 \] (The product is positive.)

Step 4: Combine the results.

The product \((x - 3)(2x + 7)\) is positive in the intervals:

  • \( (-\infty, -\frac{7}{2}) \)
  • \( (3, \infty) \)

Step 5: Write the solution.

The solution to the inequality \((x - 3)(2x + 7) > 0\) is: \[ x \in (-\infty, -\frac{7}{2}) \cup (3, \infty) \]

(x−3)(2x+7)>0.
To solve the inequality \((x - 3)(2x + 7) > 0\), we need to find the values of \(x\) for which this product is positive. **Step 1: Determine the critical points.** Set each factor equal to zero: 1. \(x - 3 = 0 \Rightarrow x = 3\) 2. \(2x + 7 = 0 \Rightarrow 2x = -7 \Rightarrow x = -\frac{7}{2}\) The critical points are \(x = 3\) and \(x = -\frac{7}{2}\). **Step 2: Test the intervals determined by these critical points.** The critical points divide the number line into three intervals: - \( (-\infty, -\frac{7}{2}) \) - \( (-\frac{7}{2}, 3) \) - \( (3, \infty) \) **Step 3: Test a point from each interval.** 1. For the interval \( (-\infty, -\frac{7}{2}) \), let’s choose \(x = -4\): \[ (-4 - 3)(2(-4) + 7) = (-7)(-8 + 7) = (-7)(-1) = 7 > 0 \] (The product is positive.) 2. For the interval \( (-\frac{7}{2}, 3) \), let’s choose \(x = 0\): \[ (0 - 3)(2(0) + 7) = (-3)(7) = -21 < 0 \] (The product is negative.) 3. For the interval \( (3, \infty) \), let’s choose \(x = 4\): \[ (4 - 3)(2(4) + 7) = (1)(8 + 7) = (1)(15) = 15 > 0 \] (The product is positive.) **Step 4: Combine the results.** The product \((x - 3)(2x + 7)\) is positive in the intervals: - \( (-\infty, -\frac{7}{2}) \) - \( (3, \infty) \) **Step 5: Write the solution.** The solution to the inequality \((x - 3)(2x + 7) > 0\) is: \[ x \in (-\infty, -\frac{7}{2}) \cup (3, \infty) \]