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2x^2+5x-3gt0...

`2x^2+5x-3gt0`

A

`(-oo,-3]uu(1/2,oo)`

B

`(-oo,-3[uu[2,oo]`

C

`R-[-3,1/2]`

D

`R-(-3,1/2)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the inequality \(2x^2 + 5x - 3 > 0\), we will follow these steps: ### Step 1: Factor the quadratic expression We start with the quadratic inequality: \[ 2x^2 + 5x - 3 > 0 \] We will factor the quadratic expression. To do this, we can look for two numbers that multiply to \(2 \times -3 = -6\) and add to \(5\). The numbers \(6\) and \(-1\) satisfy this condition. Rewriting the middle term: \[ 2x^2 + 6x - x - 3 > 0 \] ### Step 2: Group the terms Next, we group the terms: \[ (2x^2 + 6x) + (-x - 3) > 0 \] ### Step 3: Factor by grouping Now, we factor out the common factors from each group: \[ 2x(x + 3) - 1(x + 3) > 0 \] This can be factored further: \[ (2x - 1)(x + 3) > 0 \] ### Step 4: Find the critical points To solve the inequality, we need to find the critical points where the expression equals zero: \[ 2x - 1 = 0 \quad \Rightarrow \quad x = \frac{1}{2} \] \[ x + 3 = 0 \quad \Rightarrow \quad x = -3 \] ### Step 5: Test intervals Now we will test the intervals defined by the critical points \(x = -3\) and \(x = \frac{1}{2}\): 1. **Interval 1:** \( (-\infty, -3) \) - Choose \(x = -4\): \((2(-4) - 1)(-4 + 3) = (-8 - 1)(-1) = 9 > 0\) (True) 2. **Interval 2:** \( (-3, \frac{1}{2}) \) - Choose \(x = 0\): \((2(0) - 1)(0 + 3) = (-1)(3) = -3 < 0\) (False) 3. **Interval 3:** \( (\frac{1}{2}, \infty) \) - Choose \(x = 1\): \((2(1) - 1)(1 + 3) = (2 - 1)(4) = 1 \cdot 4 = 4 > 0\) (True) ### Step 6: Write the solution From our testing, the inequality \( (2x - 1)(x + 3) > 0 \) holds true in the intervals: \[ (-\infty, -3) \quad \text{and} \quad \left(\frac{1}{2}, \infty\right) \] ### Final Answer: Thus, the solution to the inequality \(2x^2 + 5x - 3 > 0\) is: \[ x \in (-\infty, -3) \cup \left(\frac{1}{2}, \infty\right) \]
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