Advanced Math practice question

Answer: A. k = 3

Two distinct real solutions need discriminant 16 − 4k > 0, i.e. k < 4. Only k = 3 qualifies.

Why the other answers are wrong

B. k = 4

k = 4 gives discriminant 0: one repeated solution.

C. k = 5

k = 5 gives 16 − 20 < 0: no real solutions.

D. k = 10

k = 10 gives 16 − 40 < 0: no real solutions.

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