Multiple choice

If one root of the quadratic equation $2{ x }^{ 2 }+kx-6=0$ is 2, then the value of k is

  1. 1

  2. -1

  3. 0

  4. -2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If 2 is a root, then 2(2)^2 + k(2) - 6 = 0. 8 + 2k - 6 = 0, so 2k + 2 = 0, which means k = -1.

AI explanation

Since x = 2 is a root of the quadratic equation, substituting 2 for x in the equation 2x^2 + kx - 6 = 0 gives 2(2)^2 + k(2) - 6 = 0. Simplifying this yields 8 + 2k - 6 = 0, which further reduces to 2k + 2 = 0. Solving for k gives k = -1.

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