Question

.. If one zero of the quadratic polynomial x² + 3x + k is 2, then the value of k is
(a) 10 (b) -10 (c) 5 (d) -5
​

Answer 1

Answer :

-10

Solution :

p(x) = x² + 3x + k

If 2 is the zero of the polynomial,

p(2) = 0

x² + 3x + k = 0 where x = 2

2² + 3(2) + k = 0

10 + k = 0

∴ k = -10

Answer 2

Answer:

(b). - 10

Step-by-step explanation:

If 2 is zero of f(x) = x² + 3x + k , then

f(2) = 2² + 3×2 + k = 0

10 + k = 0 ⇒ k = - 10