Processing math: 100%
Home / Aptitude Tests / Further Mathematics / α and \(\be...
α and β are the roots of the equation \(2x^...

α and β are the roots of the equation 2x23x+4=0. Find αβ+βα

A.

98

B.

78

C.

78

D.

98

Correct answer is B

αβ+βα=α2+β2αβ

α+β=ba; αβ=ca

α2+β2=(α+β)22(αβ)

From the equation, a = 2, b = -3, c =4

α+β=(3)2=32

αβ=42=2

α2+β2=(32)22(2))=944=74

αβ+βα=742=78