Let α and β be the roots of x 2 - 3 x + p = 0 and γ and δ be the roots of x 2 - 6 x + q…

Let α and β be the roots of x2-3x+p=0 and γ and δ be the roots of x2-6x+q=0. If α,β,γ,δ from a geometric progression. Then ratio (2 q+p):(2 q-p) is
  1. 3:1
  2. 9:7
  3. 5:3
  4. 33:31

Solution

Let α=a,β=ar,γ=ar2,δ=ar3

α+β=3  a+ar=3  ...........1

γ+δ=6ar2+ar3=6   .........2

By 1 and 2 ar21+ra1+r=63

r2=2

  2q+p2qp=2γδ+αβ2γδαβ=2a2r5+a2r2a2r5a2r=2r4+12r41=8+181=97

Asked in: JEE Main 2020 (04 Sep Shift 1)

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