Let f x be a quadratic polynomial such that f – 1 + f 2 = 0 . If one of the roots of f x = 0 is 3 ,…

Let fx be a quadratic polynomial such that f1+f2=0. If one of the roots of fx=0 is 3, then its other root lies in
  1. -1,0
  2. 1,3
  3. 3,1
  4. 0,1

Solution

Let fx=ax2+bx+c be a quadratic equation with roots α, β

f2+f-1=05a+b+2c=0

 Also f3=09a+3b+c=0

a-5=b13=c6

Product of roots αβ=ca=-65

We know α=3β=-25-1,0

Asked in: JEE Main 2020 (02 Sep Shift 2)

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