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The roots of the equation 2x2+kx+5=0 are \(\alp...

The roots of the equation 2x2+kx+5=0 are α and β, where k is a constant. If α2+β2=1, find the values of k.

A.

±16

B.

±8

C.

±4

D.

±2

Correct answer is C

2x2+kx+5=0

α+β=ba=k2

αβ=ca=52

α2+β2=(α+β)22αβ

1=(k2)22(52)

1=k245k24=4

k2=16