For what values of b, the quadratic equation 4x² + bx + 16 = 0 has equal real roots?

Correct option is B

Given:

Quadratic equation: $$4x^2 + bx + 16$$​= 0

Concept Used:

A quadratic equation has equal real roots when its discriminant D = 0

Discriminant D of $$ax^2 + bx + c = 0$$​ is:

D = $$b^2 - 4ac$$​​

Solution:

Here, a = 4, b = b, c = 16

​$$b^2 - 4 \times 4 \times 16 = 0$$​​

​$$b^2 - 256 = 0$$​​

​$$b^2 = 256 \\ \ \\ b = \pm \sqrt{256} = \pm 16$$​​

b = 16 or b = -16