Q29 / 87 · NTA Abhyas (JEE Main) 2020 · Mathematics · Functions

For real values of x, the value of the expression 11x2-12x-6x2+4x+2

  • A
    lies between -17 and -3
  • Correct answer
    B
    does not lie between -17 and -3
  • C
    lies between 3 and 17
  • D
    does not lie between 3 and 17

Solution

Let y=11x2-12x-6x2+4x+2
yx2+4yx+2y=11x2-12x-6
y-11x2+4y+12x+2y+6=0
x∈R⇒D≥0
⇒4y+32-4y-112y+3≥0
⇒8y+32y+3-y-11≥0
⇒8y+3y+17≥0
⇒y≤-17 or y≥-3
⇒y does not lie between -17 and -3

Hence, the correct answer is option: 'B'.

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