Solve 2x^2 - 4x - 6 = 0.

• A. 1 or -3
• B. -3 or 2
• C. -1 or 3
• D. -2 or 3

Answer: (C)

Solving a quadratic means finding the x-values that make the expression zero, the points where the parabola crosses the x-axis. Start by factoring out the 2: 2x^2 - 4x - 6 = 0 becomes 2(x^2 - 2x - 3) = 0. Factor the inner quadratic: x^2 - 2x - 3 = (x - 3)(x + 1). So the equation is 2(x - 3)(x + 1) = 0. A product is zero when any factor is zero, giving x = 3 or x = -1. Those are the solutions, which corresponds to the choice that lists -1 and 3. A quick check with the quadratic formula would also yield x = 3 and x = -1.