Question

If `1/2` is a root of the equation `"x"^2 + "kx" - (5/4)` = 0 then the value of k is:

Options

• 2

• –2

• 3

• –3

Answer 1

2

Explanation:

As one root of the equation `"x"^2 + "kx" - (5/4)` = 0 is `1/2`

⇒ `(1/2)^2 + "k"(1/2) - 5/4` = 0

⇒ `1/4 + "k"/2 - 5/4` = 0

⇒ 1 + 2k – 5 = 0

⇒ 2k = 4

⇒ k = 2