Question

Q1.
If the sum of the zeroes of the polynomial f(x) = 2x - 3kx2 + 4x - 5 is 6, then the value of k is
a) 2
b) -2
d) 4.​

Answer 1

Refer to the attachment:

#BAL #answerwithquality

Answer 2

If the sum of the zeroes of the polynomial f(x) = 2x3

– 3kx2 + 4x – 5 is 6, then value of k is

Given :

Sum of the zeroes of the polynomial f(x) = 2x³– 3kx² + 4x – 5 is 6.

To find :

Value of k .

Concept :

For a cubic polynomial is in the form of ax³ + bx² + cx + d :

∵ Sum of zeros = -b/a  where, b is coefficient of x² and a is the coefficient of x³

Solution :

Now , f(x) = 2x³ - 3kx² + 4x - 5

Or, f(x) = 2x³ + (-3kx²) + 4x + (-5)

Now according to concept :

⇒ -coefficient of x²/coefficient of x³ = 6

⇒ -(-3k)/2 = 6

⇒ 3k/2 = 6

⇒ 3k = 6 × 2

⇒ 3k = 12

⇒ k = 12/3

⇒ k = 4

∴ Required value of k = 4