Class JEE Mathematics ALL Q #1199
KNOWLEDGE BASED
APPLY
4 Marks 2026 JEE Main 2026 (Online) 22 January Morning Shift NUMERICAL
The number of real solutions of equation $x|x+4|+3|x+2|+10=0$ is equal to .

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Step-by-Step Solution

**Case 1:** $x \ge -2$ In this case, $|x+4| = x+4$ and $|x+2| = x+2$. The equation becomes: $x(x+4) + 3(x+2) + 10 = 0$ $x^2 + 4x + 3x + 6 + 10 = 0$ $x^2 + 7x + 16 = 0$ The discriminant is $D = 7^2 - 4(1)(16) = 49 - 64 = -15 < 0$. So, there are no real solutions in this case.
**Case 2:** $-4 \le x < -2$ In this case, $|x+4| = x+4$ and $|x+2| = -(x+2)$. The equation becomes: $x(x+4) + 3(-(x+2)) + 10 = 0$ $x^2 + 4x - 3x - 6 + 10 = 0$ $x^2 + x + 4 = 0$ The discriminant is $D = 1^2 - 4(1)(4) = 1 - 16 = -15 < 0$. So, there are no real solutions in this case.
**Case 3:** $x < -4$ In this case, $|x+4| = -(x+4)$ and $|x+2| = -(x+2)$. The equation becomes: $x(-(x+4)) + 3(-(x+2)) + 10 = 0$ $-x^2 - 4x - 3x - 6 + 10 = 0$ $-x^2 - 7x + 4 = 0$ $x^2 + 7x - 4 = 0$ Using the quadratic formula: $x = \frac{-7 \pm \sqrt{7^2 - 4(1)(-4)}}{2(1)} = \frac{-7 \pm \sqrt{49 + 16}}{2} = \frac{-7 \pm \sqrt{65}}{2}$ $x_1 = \frac{-7 + \sqrt{65}}{2} \approx \frac{-7 + 8.06}{2} \approx \frac{1.06}{2} \approx 0.53$ $x_2 = \frac{-7 - \sqrt{65}}{2} \approx \frac{-7 - 8.06}{2} \approx \frac{-15.06}{2} \approx -7.53$ Since we are considering $x < -4$, $x_1$ is not a solution, but $x_2 = \frac{-7 - \sqrt{65}}{2}$ is a solution because it is less than -4.
Therefore, there is only one real solution.

Correct Answer: 1

Pedagogical Audit
Bloom's Analysis: This is an APPLY question because the student needs to apply their knowledge of absolute value functions and quadratic equations to solve the given equation by considering different cases.
Knowledge Dimension: PROCEDURAL
Justification: The student needs to follow a specific procedure to solve the equation, which involves considering different cases based on the absolute value functions and then solving the resulting quadratic equations.
Syllabus Audit: In the context of JEE, this is classified as KNOWLEDGE. The question directly tests the student's understanding and application of algebraic techniques to solve equations involving absolute values, a standard topic in algebra.

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