Verified Solution • 2025–26 Session moderate

QJEEM18Ma2ec5: JEE Main 2018 Mathematics - Class 11 JEEM18Ma2ec5 Solution: If f(x) is a quadratic expression such that f (1) + f (2) = 0,…

If f(x) is a quadratic expression such that f (1) + f (2) = 0, and − 1 is a root of f (x) = 0, then the other root of f(x) = 0 is :

Multiple Choice Options

  • A − 58
  • B − 85
  • C 58
  • D 85

Step-by-Step Verified Solution

Let α and β = - 1 are the roots of the polynomial, then we get

f(x) = x2 + (1 - α)x - α

∴ f(1) = 2 - 2α

and f(2) = 6 - 3α

Also given,

f (1) + f (2) = 0

∴ 2 - 2α + 6 - 3α = 0

⇒ α = 85

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