Question

Find the values of k for which the roots are real and equal in each of the following equation:

2kx² - 40x + 25 = 0

Answer 1

The given quadric equation is 2kx² - 40x + 25 = 0, and roots are real and equal

Then find the value of k.

Here, a = 2k, b = -40 and c = 25

As we know that D = b² - 4ac

Putting the value of a = 2k, b = -40 and c = 25

= (-40)² - 4 x (2k) x (25)

=1600 - 200k

The given equation will have real and equal roots, if D = 0

Thus,

1600 - 200k = 0

200k = 1600

k = 1600/200

k = 8

Therefore, the value of k = 8.