For what positive value of k does x² − kx + 9 = 0 have equal roots?

6. Equal roots require the discriminant k² − 4×9 = 0, so k² = 36 and the positive value is k = 6.

For what positive value of $k$ does $x^{2} - k x + 9 = 0$ have equal roots?

Competition practiceAlgebra

Equal roots require the discriminant

k^{2} - 4 \times 9 = 0

, so

k^{2} = 36

and the positive value is

k = 6

Answer: B) 6

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