Questions: Select the correct answer. What are the solutions of the quadratic equation below? 2 x^2 - 2 x - 9 = 0 A. (-1 ± √19)/2 B. (3 ± √19)/2 C. (1 ± √19)/2 D. (1 ± 3√19)/2

Select the correct answer.

What are the solutions of the quadratic equation below?
2 x^2 - 2 x - 9 = 0
A. (-1 ± √19)/2
B. (3 ± √19)/2
C. (1 ± √19)/2
D. (1 ± 3√19)/2
Transcript text: Select the correct answer. What are the solutions of the quadratic equation below? \[ 2 x^{2}-2 x-9=0 \] A. $\frac{-1 \pm \sqrt{19}}{2}$ B. $\frac{3 \pm \sqrt{19}}{2}$ C. $\frac{1 \pm \sqrt{19}}{2}$ D. $\frac{1 \pm 3 \sqrt{19}}{2}$
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Solution

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Solution Steps

Step 1: Identify the coefficients

The quadratic equation is given as: \[ 2x^{2} - 2x - 9 = 0 \] Here, the coefficients are:

  • \( a = 2 \)
  • \( b = -2 \)
  • \( c = -9 \)
Step 2: Apply the quadratic formula

The quadratic formula is: \[ x = \frac{-b \pm \sqrt{b^{2} - 4ac}}{2a} \] Substitute the values of \( a \), \( b \), and \( c \) into the formula: \[ x = \frac{-(-2) \pm \sqrt{(-2)^{2} - 4 \cdot 2 \cdot (-9)}}{2 \cdot 2} \]

Step 3: Simplify the expression

Calculate the discriminant and simplify: \[ x = \frac{2 \pm \sqrt{4 + 72}}{4} \] \[ x = \frac{2 \pm \sqrt{76}}{4} \] \[ x = \frac{2 \pm 2\sqrt{19}}{4} \] \[ x = \frac{1 \pm \sqrt{19}}{2} \]

Final Answer

The correct answer is C. \( \boxed{\frac{1 \pm \sqrt{19}}{2}} \)

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