# Find the value of k for which the roots of 9x2 + 8kx + 16 = 0 are real and equal.

Given that the quadratic equation 9x2 + 8kx + 16 = 0 roots are real and equal.

Comparing with standard quadratic equation ax2 + bx + c = 0

a = 9 b = 8k c = 16

Thus D = 0

Discriminant D = b2 – 4ac = 0

(8k)2 – 4.9.16 = 0

64k2 – 576 = 0

k2 = 9 taking square root both sides Thus k = 3 or k = – 3 for which the roots are real and equal.

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos  Get To Know About Quadratic Formula42 mins  Quiz | Knowing the Nature of Roots44 mins  Take a Dip Into Quadratic graphs32 mins  Foundation | Practice Important Questions for Foundation54 mins  Nature of Roots of Quadratic EquationsFREE Class  Getting Familiar with Nature of Roots of Quadratic Equations51 mins  Quadratic Equation: Previous Year NTSE Questions32 mins  Champ Quiz | Quadratic Equation33 mins  Balance the Chemical Equations49 mins  Champ Quiz | Quadratic Equation48 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation view all courses 