Question

If -1/2 is one root of quadratic equation 2x^2+kx+1=0, find k.

Answer 1

-3 is the answer for the above question

Answer 2

2x^2 + kx +1 = 0

Now -1/2 is a root of the equation so it will satisfy the equation.

Put -1/2 in an equation.

2(-1/2)^2 + k(-1/2) + 1 = 0

2 / 4 - 1/2k + 1= 0

1/2 - 1/2k + 1 = 0

3/2 - 1/2k = 0

-1/2k = -3/2

k = 3


Thanks