Solve the following quadratic equation.

3x^2=-72



A
−24-24−24

B
±26\pm2\sqrt{6}±2
6



C
±6i2\pm6i\sqrt{2}±6i
2



D
±2i6\pm2i\sqrt{6}±2i
6

1 answer

To solve the quadratic equation \(3x^2 = -72\), we first rearrange it:

\[ 3x^2 + 72 = 0 \]

Next, we divide all terms by 3:

\[ x^2 + 24 = 0 \]

Now, we can isolate \(x^2\):

\[ x^2 = -24 \]

Next, we take the square root of both sides. Remember that the square root of a negative number involves imaginary numbers:

\[ x = \pm \sqrt{-24} \] \[ x = \pm \sqrt{24}i \] \[ x = \pm \sqrt{4 \cdot 6}i \] \[ x = \pm 2\sqrt{6}i \]

Thus, the solutions to the equation are:

\[ x = \pm 2\sqrt{6}i \]

Looking at the options provided:

  • A: \(-24-24−24\)
  • B: \(\pm 26 \pm 2\sqrt{6} \pm 2\)
  • C: \(\pm 6i \sqrt{2} \pm 6i\)
  • D: \(\pm 2i \sqrt{6} \pm 2i\)

The correct solution matches with:

\[ \text{D: } \pm 2i \sqrt{6} \]

So, the answer is D.