Q4 of 109 Page 3

If the sum of the zeros of the polynomial f(x) = 2x3 – 3kx2 + 4x – 5 is 6, then the value of k is

Given,


f(x) = 2x3 – 3kx2 + 4x – 5


Sum of the zeros of the polynomial = 6


Let x, y and z be the zeroes than,


x + y + z = 6……Equation (i)


So,


x + y + z = – b/a


= – ( – 3k)/2


From Eq. (i) we get,


3k/2 = 6


k/2 = 6/3


k = 2×2 = 4

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