Which equation has the solutions [tex]\( x = \frac{-3 \pm \sqrt{3}i}{2} \)[/tex]?

A. [tex]\(2x^2 + 6x + 9 = 0\)[/tex]
B. [tex]\(x^2 + 3x + 12 = 0\)[/tex]
C. [tex]\(x^2 + 3x + 3 = 0\)[/tex]
D. [tex]\(2x^2 + 6x + 3 = 0\)[/tex]



Answer :

To determine which equation has the solutions [tex]\( x = \frac{-3 \pm \sqrt{3}i}{2} \)[/tex], let's test each given equation by substituting these complex solutions and checking if the equation holds true.

First, let’s denote the solutions:
[tex]\[ x_1 = \frac{-3 + \sqrt{3}i}{2} \][/tex]
[tex]\[ x_2 = \frac{-3 - \sqrt{3}i}{2} \][/tex]

We'll evaluate each equation at both values.

1. Equation: [tex]\( 2x^2 + 6x + 9 = 0 \)[/tex]

Substituting [tex]\( x_1 \)[/tex]:
[tex]\[ 2\left(\frac{-3 + \sqrt{3}i}{2}\right)^2 + 6\left(\frac{-3 + \sqrt{3}i}{2}\right) + 9 = 0 \][/tex]

Substituting [tex]\( x_2 \)[/tex]:
[tex]\[ 2\left(\frac{-3 - \sqrt{3}i}{2}\right)^2 + 6\left(\frac{-3 - \sqrt{3}i}{2}\right) + 9 = 0 \][/tex]

Both these evaluations need to equal zero in order for [tex]\( x_1 \)[/tex] and [tex]\( x_2 \)[/tex] to be solutions. After performing the above substitutions and calculations we would verify if they indeed equal zero.

2. Equation: [tex]\( x^2 + 3x + 12 = 0 \)[/tex]

Substituting [tex]\( x_1 \)[/tex]:
[tex]\[ \left(\frac{-3 + \sqrt{3}i}{2}\right)^2 + 3\left(\frac{-3 + \sqrt{3}i}{2}\right) + 12 = 0 \][/tex]

Substituting [tex]\( x_2 \)[/tex]:
[tex]\[ \left(\frac{-3 - \sqrt{3}i}{2}\right)^2 + 3\left(\frac{-3 - \sqrt{3}i}{2}\right) + 12 = 0 \][/tex]

Both must evaluate to zero.

3. Equation: [tex]\( x^2 + 3x + 3 = 0 \)[/tex]

Substituting [tex]\( x_1 \)[/tex]:
[tex]\[ \left(\frac{-3 + \sqrt{3}i}{2}\right)^2 + 3\left(\frac{-3 + \sqrt{3}i}{2}\right) + 3 = 0 \][/tex]

Substituting [tex]\( x_2 \)[/tex]:
[tex]\[ \left(\frac{-3 - \sqrt{3}i}{2}\right)^2 + 3\left(\frac{-3 - \sqrt{3}i}{2}\right) + 3 = 0 \][/tex]

Again, both must be zero.

4. Equation: [tex]\( 2x^2 + 6x + 3 = 0 \)[/tex]

Substituting [tex]\( x_1 \)[/tex]:
[tex]\[ 2\left(\frac{-3 + \sqrt{3}i}{2}\right)^2 + 6\left(\frac{-3 + \sqrt{3}i}{2}\right) + 3 = 0 \][/tex]

Substituting [tex]\( x_2 \)[/tex]:
[tex]\[ 2\left(\frac{-3 - \sqrt{3}i}{2}\right)^2 + 6\left(\frac{-3 - \sqrt{3}i}{2}\right) + 3 = 0 \][/tex]

Both need to simplify to zero.

Evaluating these, we discover that the correct equation where both solutions [tex]\( x_1 \)[/tex] and [tex]\( x_2 \)[/tex] satisfy the equation is:

[tex]\[ x^2 + 3x + 3 = 0 \][/tex]

Therefore, the correct equation is:
[tex]\[ x^2 + 3x + 3 = 0 \][/tex]

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