Question

6. Find the value of k for which the root for which the rooi of the quadratic equation 2kx²” – kr – 1 = 0 has real and equal roots.​

Answer 1

The given quadratic equation is 2kx

2 −40x+25=0, comparing it with ax

2 +bx+c=0

⇒ We get, a=2k,b=−40 and c=25.

⇒ It is given that the roots are real and equal.

∴ b

2 −4ac=0

⇒ (−40)

2 −4(2k)(25)=0

⇒ 1600−200k=0

⇒ 200k=1600

⇒ k=8