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ICSE Class 10 Mathematics Question 9 of 49

Multiple-Choice Questions — Question 9

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Question

Question 9

The value/s of 'k' for which the quadratic equation 2x2 - kx + k = 0 has equal roots is (are) :

  1. 0 only

  2. 4, 0

  3. 8 only

  4. 0, 8

Answer

Given,

Equation : 2x2 - kx + k = 0

a = 2, b = -k and c = k.

For equal roots,

⇒ Discriminant (D) = 0

⇒ b2 - 4ac = 0

⇒ (-k)2 - 4 × 2 × k = 0

⇒ k2 - 8k = 0

⇒ k(k - 8) = 0

⇒ k = 0 or k - 8 = 0

⇒ k = 0 or k = 8.

Hence, Option 4 is the correct option.