Solve the quadratic equation 6x2−3x+6=0 . Which of the following expresses its solutions in the form a±bi ?(1 point)

Responses

12±15√2i
Start Fraction 1 over 2 End Fraction plus or minus Start Fraction Start Root 15 End Root over 2 End Fraction i

14±15√4i
Start Fraction 1 over 4 End Fraction plus or minus Start Fraction Start Root 15 End Root over 4 End Fraction i

−14±15√4i
negative Start Fraction 1 over 4 End Fraction plus or minus Start Fraction Start Root 15 End Root over 4 End Fraction i

14±17√4i

1 answer

To solve the quadratic equation \( 6x^2 - 3x + 6 = 0 \), we will use the quadratic formula:

\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \]

where \( a = 6 \), \( b = -3 \), and \( c = 6 \).

  1. First, we calculate \( b^2 - 4ac \):

\[ b^2 = (-3)^2 = 9 \] \[ 4ac = 4 \times 6 \times 6 = 144 \] \[ b^2 - 4ac = 9 - 144 = -135 \]

  1. Since the determinant \( b^2 - 4ac \) is negative, there will be complex solutions.

  2. Now we substitute \( a \), \( b \), and the value of the determinant into the quadratic formula:

\[ x = \frac{-(-3) \pm \sqrt{-135}}{2 \times 6} \] \[ x = \frac{3 \pm \sqrt{-135}}{12} \]

  1. We can simplify \( \sqrt{-135} \):

\[ \sqrt{-135} = \sqrt{135} \cdot i = \sqrt{9 \cdot 15} \cdot i = 3\sqrt{15} \cdot i \]

  1. Substitute this back into the equation:

\[ x = \frac{3 \pm 3\sqrt{15} \cdot i}{12} \]

  1. We can simplify \( \frac{3}{12} \) and \( \frac{3\sqrt{15}}{12} \):

\[ x = \frac{1}{4} \pm \frac{\sqrt{15}}{4} \cdot i \]

Thus, the solutions can be expressed in the form \( a \pm bi \) as:

\[ x = \frac{1}{4} \pm \frac{\sqrt{15}}{4} i \]

Therefore, the correct response from your options is:

Start Fraction 1 over 4 End Fraction plus or minus Start Fraction Start Root 15 End Root over 4 End Fraction i