Q8 of 39 Page 91

Find the value of k for which one root of the quadratic equation kx2 – 14x + 8 = 0 is six times the other.

Let one of the root be ‘a’

So another root = 6a


As, the sum of roots =


⇒ 7a = 14/k


⇒ a = 2/k ...... (i)


Also,


⇒ 6a2 = 8/k


putting the value of a from (i)



⇒ 3k = k2


⇒ k(k – 3) = 0


⇒ k = 0 or k = 3


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