The equation x squared + kx + 9 = 0, with k greater than 0, has exactly one solution. What is k?
Answer and explanation
Correct answer: B. k = 6
- Step 1: One solution means the discriminant b squared - 4ac = 0. Step 2. Here k squared - 4 x 1 x 9 = 0, so k squared = 36 and k = 6. Answer: k = 6. Why not the others: k = 3 and k = 9 are guesses from the constant; k = 18 does not give a zero discriminant.
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