Question

If `1/2` a root of the equation `x^2 + kx - 5/4` = 0, then the value of k is ______.

Options

• 2

• – 2

• `1/4`

• `1/2`

Answer 1

If `1/2` a root of the equation `x^2 + kx - 5/4` = 0, then the value of k is 2.

Explanation:

If `1/2` is a root of the equation

x² + kx – `5/4` = 0 then

Substituting the value of `1/2` in place of x should give us the value of k.

Given, x² + kx – `5/4` = 0 where, x = ½

`(1/2)^2 + k(1/2) - (5/4)` = 0

`(k/2) = (5/4) – 1/4`

k = 2