if a, b are the roots of x^2 - 3x + p =0 and c, d are the roots of x^2 - 12x +q = 0 where a,b,c,d form a G.P, find the ratio of (q+p):(q-p)

It is given that a and b are the roots of x2 – 3x + p = 0

a + b = 3 and ab = p … (1)

Also, c and d are the roots of

c + d = 12 and cd = q … (2)

It is given that a, b, c, d are in G.P.

Let a = x, b = xr, c = xr2, d = xr3

From (1) and (2), we obtain

x + xr = 3

 x (1 + r) = 3

xr2 + xr3 =12

 xr2 (1 + r) = 12

On dividing, we obtain


When r = 2 and x =1,

ab = x2r = 2

cd = x2r5 = 32


similarly when  r = -2 & x =  -3  wecan do it by getting same result

 

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