Responder
The first statement is **False**. The correct solution for the second inequality is option **d**: \( \{x \mid x \leq -3 \text{ or } x \geq 2\} \). The quadratic inequality \(12 - 2x^2 - y \leq 0\) is indeed a quadratic inequality.
Solución
Let's break down the problem step by step.
### Part 1: Analyzing the first inequality
The inequality given is:
\[
-2x^2 + 2 \geq -3x
\]
First, we can rearrange this inequality to standard form:
\[
-2x^2 + 3x + 2 \geq 0
\]
Next, we can multiply through by -1 (remembering to reverse the inequality):
\[
2x^2 - 3x - 2 \leq 0
\]
Now, we will solve the quadratic equation \(2x^2 - 3x - 2 = 0\) to find the critical points. We can use the quadratic formula:
\[
x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
\]
where \(a = 2\), \(b = -3\), and \(c = -2\).
Calculating the discriminant:
\[
b^2 - 4ac = (-3)^2 - 4(2)(-2) = 9 + 16 = 25
\]
Now, substituting into the quadratic formula:
\[
x = \frac{3 \pm \sqrt{25}}{2 \cdot 2} = \frac{3 \pm 5}{4}
\]
This gives us two solutions:
\[
x_1 = \frac{8}{4} = 2, \quad x_2 = \frac{-2}{4} = -\frac{1}{2}
\]
Now we have the critical points \(x = -\frac{1}{2}\) and \(x = 2\).
Next, we will test intervals around these critical points to determine where the inequality holds:
1. **Interval \( (-\infty, -\frac{1}{2}) \)**: Choose \(x = -1\):
\[
2(-1)^2 - 3(-1) - 2 = 2 + 3 - 2 = 3 \quad (\text{True})
\]
2. **Interval \( (-\frac{1}{2}, 2) \)**: Choose \(x = 0\):
\[
2(0)^2 - 3(0) - 2 = -2 \quad (\text{False})
\]
3. **Interval \( (2, \infty) \)**: Choose \(x = 3\):
\[
2(3)^2 - 3(3) - 2 = 18 - 9 - 2 = 7 \quad (\text{True})
\]
Thus, the solution to the inequality \(2x^2 - 3x - 2 \leq 0\) is:
\[
x \in \left[-\frac{1}{2}, 2\right]
\]
This means the statement \( \left\{x \mid -\frac{1}{2} \leq x \geq 2\right\} \) is **False**.
### Part 2: Solving the second inequality
Now, we need to solve the inequality:
\[
x^2 \geq -x + 6
\]
Rearranging gives:
\[
x^2 + x - 6 \geq 0
\]
Next, we factor the quadratic:
\[
(x + 3)(x - 2) \geq 0
\]
The critical points are \(x = -3\) and \(x = 2\). We will test intervals around these points:
1. **Interval \( (-\infty, -3) \)**: Choose \(x = -4\):
\[
(-4 + 3)(-4 - 2) = (-1)(-6) = 6 \quad (\text{True})
\]
2. **Interval \( (-3, 2) \)**: Choose \(x = 0\):
\[
(0 + 3)(0 - 2) = (3)(-2) = -6 \quad (\text{False})
\]
3. **Interval \( (2, \infty) \)**: Choose \(x = 3\):
\[
(3 + 3)(3 - 2) = (6)(1) = 6 \quad (\text{True})
\]
Thus, the solution to the inequality \(x^2 + x - 6 \geq 0\) is:
\[
x \in (-\infty, -3] \cup [2, \infty)
\]
This corresponds to option **d**: \( \{x \mid x \leq -3 \text{ or } x \geq 2\} \).
### Part 3: Analyzing the quadratic inequality
The inequality \(12 - 2x^2 - y \leq 0\) can be rearranged to:
\[
y \geq 12 - 2x^2
\]
This represents a downward-opening parabola in the xy-plane. The statement that it is a quadratic inequality is **True**.
### Summary of Answers:
1. The first statement is **False**.
2. The correct option for the second inequality is **d**.
3. The statement about the quadratic inequality is **True**.
Respondido por UpStudy AI y revisado por un tutor profesional

Explicar

Simplifique esta solución