Question

If one zero of the quadratic polynomial kx² + 3x + k is 2, then the value of k is

(a) \(\frac{5}6\)

(b) \(\frac{-5}6\)

(c) \(\frac{6}5\)

(d) \(\frac{-6}5\)

Answer 1

 (d) \(\frac{-6}5\) 

Since 2 is a zero of kx² + 3x + k, 

we have:

 k× (2)² + 3(2) + k = 0 

⇒ 4k + k + 6 = 0 

⇒ 5k = - 6

⇒ k = \(\frac{-6}5\)