JEE Main · MathematicsEasy

$If the roots of the quadratic equation x^{2} - 6 x + k = 0 are equal, find the value of k .$

A. $6$
B. $12$
C. $9$
D. $3$

Show correct answer & step-by-step solution

Correct answer: C — $9$

Solution

For equal roots, the discriminant b^{2} - 4 a c must be zero. Substituting the values, (- 6)^{2} - 4 (1) (k) = 0, which leads to $36 - 4k = 0$, so k = 9 .

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