1.

If the roots of the quadratic equation x2 - kx + 4 = 0 are equal, then find the value of 'k'.1. ± 32. ± 43. ± 24. 0

Answer» Correct Answer - Option 2 : ± 4

Concept:

Let us consider the standard form of a quadratic equation, ax2 + bx + c =0

Discriminant = D = b2 – 4ac

  • If the Discriminant > 0 then the roots are real and distinct.
  • If the Discriminant = 0 then the roots are real and equal.
  • If the Discriminant < 0 then the roots are Imaginary.

 

Calculation:

Given:

The roots of the quadratic equation x2 - kx + 4 = 0 are equal.

For equal roots, Discriminant = 0

⇒ D = b2 – 4ac = 0

⇒ (-k)2 - 4 × 1 × 4 = 0

⇒ k2 - 16 = 0

⇒ k2 = 16

∴ k = ± 4


Discussion

No Comment Found

Related InterviewSolutions