Q13 of 52 Page 1

Find the value of k for which the roots of the equation kx(3x – 4) + 4 = 0, are equal.

kx (3x - 4) + 4 = 0


3kx2 + 4kx + 4 = 0


a = 3k


b = -4k


c = 4


D = 0 (Since Roots are equal)


b2 – 4ac = 0


∴ (-4k)2 – 4(3k)(4) = 0


16 k2 – 48k = 0


16 k(k – 3) = 0


16 k = 0 or k – 3 = 0


k = 0 or k = 3


As coefficient of x2 can’t be zero so, Rejecting k = 0 and,


∴ k = 3


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