Q1 of 242 Page 9

Write the value of k for which the quadratic equation x2 – kx + 4 = 0 has equal roots.

Quadratic equation has equal roots then d = b2 – 4ac = 0

Here a = 1, b = k and c = 4


So b2 – 4ac = 0


⇒ k2 – 4 × 1 × 4 = 0


⇒ k2 – 16 = 0


⇒ k = 4


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