Solve each quadratic equation. If roots are not real, use $i$.
$2x^2+18=0$

• A. $x=\pm 3$
• B. $x=\pm \frac{9}{2}$
• C. $x=\pm 3i$
• D. $x=\pm \frac{9}{2}i$

Answer: (C)

Verified step by step guidance

1. Start with the given quadratic equation: \$2x^2 + 18 = 0$.
2. Isolate the \(x^2\) term by subtracting 18 from both sides: \$2x^2 = -18$.
3. Divide both sides by 2 to solve for \(x^2\): \(x^2 = \frac{-18}{2} = -9\).
4. Since \(x^2\) equals a negative number, recognize that the solutions will be imaginary. Take the square root of both sides: \(x = \pm \sqrt{-9}\).
5. Rewrite the square root of a negative number using \(i\), where \(i = \sqrt{-1}\): \(x = \pm 3i\).