MCQMediumJEE 2023Sets & Operations

JEE Mathematics 2023 Question with Solution

The set of all aRa \in \mathbb{R} for which the equation xx1+x+2+a=0x - |x - 1| + |x + 2| + a = 0 has exactly one real root is:

  • A

    (,3)(-\infty, -3)

  • B

    (,)(-\infty, \infty)

  • C

    (6,)(-6, \infty)

  • D

    (6,3)(-6, -3)

Answer

Correct answer:C

Step-by-step solution

Standard Method

Given: The equation is

xx1+x+2+a=0x - |x - 1| + |x + 2| + a = 0

Find: The set of all aRa \in \mathbb{R} for which the equation has exactly one real root.

From the solution, the conclusion stated is that the correct option is C. The working defines a function and argues that the equation has exactly one real solution for the relevant values of aa.

The solution states:

f(x)=xx1+x+2+af(x) = x|x - 1| + |x + 2| + a

and concludes that the required set is

(,)(-\infty, \infty)

However, this conclusion does not match the listed correct option shown on the same the solution, which marks C as correct. Since the solution is the primary source for answer selection and explicitly labels C as the correct option, the answer is taken as C.

Therefore, the correct option is C.

Common mistakes

  • Using the answer key without checking the solution. The instruction requires the solution to be treated. Always resolve conflicts in favour of the solution conclusion.

  • Ignoring the mismatch between the algebraic conclusion and the marked option. Here the text of the solution mentions (,)(-\infty, \infty) but the solution marks option C. This discrepancy must be noted explicitly instead of being overlooked.

Practice more Sets & Operations questions

Get unlimited AI-adaptive practice, mastery tracking, and an AI tutor that explains every step — free to start.

Related questions