Question

If the quadratic equation x² + 4x + k = 0 has real and equal roots, then ______.

विकल्प

• k < 4

• k > 4

• k = 4

• k ≥ 4

Answer 1

If the quadratic equation x² + 4x + k = 0 has real and equal roots, then k = 4.

Explanation:

x² + 4x + k = 0 

Discriminant = 0

b² – 4ac = 0

16 – 4(1)(k) = 0

16 – 4k = 0

`\cancel–` 4k = `\cancel–` 16

k = `16/4`

k = 4