a. \( \quad 2 x^{2}-18=0 \)

To solve the equation \( 2x^2 - 18 = 0 \), you can first isolate the \( x^2 \) term. Start by adding 18 to both sides to get \( 2x^2 = 18 \). Then, divide both sides by 2, yielding \( x^2 = 9 \). Finally, take the square root of both sides to find \( x = 3 \) or \( x = -3 \). Now you have two solutions: \( x = 3 \) and \( x = -3 \). Quadratics like this one are fun because they often represent simple parabolas, and each solution represents the points where the parabola intersects the x-axis!