If the roots of the quadratic equation 2x² + 4x + k = 0 are equal, what is the value of k?
Answer: C. -8
For the roots to be equal, the discriminant must be zero. The discriminant is b² - 4ac. Here, b = 4, a = 2, and c = k. Setting 4² - 4(2)(k) = 0 gives k = -8.