The sum of the roots of the equation, x + 1 - 2 log 2 3 + 2 x + 2 log 4 10 - 2 - x = 0 , is :

The sum of the roots of the equation, x+1-2log23+2x+2log410-2-x=0, is :

  1. log214
  2. log212
  3. log213
  4. log211

Solution

Given, x+1-2log23+2x+2log410-2-x=0

x+1-2log23+2x+2log2210.2x-12x=0

x+1-2log23+2x+log210.2x-12x=0

x+1-2log23+2x+log210.2x-1-log22x=0

x+1-log23+2x2+log210.2x-1-xlog22=0

x+1-log23+2x2+log210.2x-1-x=0

x+1+log210.2x-13+2x2-x=0

1+log210.2x-13+2x2=0

log210.2x-13+2x2=-1

log210.2x-19+2x2+6.2x=log212

10.2x-19+2x2+6.2x=12

210.2x-1=9+2x2+6.2x

2x2-14.2x+11=0

Let 2x=y

y2-14y+11=0

Let roots are y1=2x1 & y2=2x2

Product of roots, y1y2=2x1×2x2=2x1+x2=11

log2x1+x2=log11

x1+x2log2=log11

x1+x2=log11log2

Hence, x1+x2=log211

Asked in: JEE Main 2021 (31 Aug Shift 2)

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