Question

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

A. 2

B. 4

C. – 2

D. – 4

Answer 1

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