Question

If one zero of the quadratic polynomial x² + 3x + k is 2, the value of k is
1. 10
2. -10
3. 5
4. -5​

Answer 1

Answer:

k = -10

Step-by-step explanation:

Given :

One zero of the quadratic polynomial x² + 3x + k is 2

To find :

the value of k

Solution :

If 'a' is a zero of the polynomial p(x), then p(a) = 0

Let the given polynomial be p(x)

p(x) = x² + 3x + k

• 2 is a zero of the polynomial

Put x = 2,

2² + 3(2) + k = 0

4 + 6 + k = 0

 10 + k = 0

  k = 0 - 10

  k = -10

∴ The value of k is -10