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Quadratic Equations appeared 26 times across 3 years — 3% of Mathematics. This question is from Equations Involving Modulus.

Year 2026 2025 2024 Total
Questions 11 10 5 26

The sum of all the roots of the equation (x-1)²-5|x-1|+6=0 , is:

Solution & Explanation

Related Formula

X² = |X|² Quadratic factorization: t² - 5t + 6 = (t-2)(t-3)

Core Logic

Rewrite the equation taking |x - 1| = t, where t ≥ 0. Since (x-1)² = |x-1|², the equation becomes:

t² - 5t + 6 = 0
Step 1: Solve for modulus
(t - 2)(t - 3) = 0 ⇒ t = 2, 3

Since both roots are positive, both provide valid solutions for the modulus. |x - 1| = 2 and |x - 1| = 3

Step 2: Unpack x values

From |x - 1| = 2:

x - 1 = 2 ⇒ x = 3 x - 1 = -2 ⇒ x = -1

From |x - 1| = 3:

x - 1 = 3 ⇒ x = 4 x - 1 = -3 ⇒ x = -2

The roots are 3, -1, 4, -2.

Step 3: Sum of Roots
Sum = 3 + (-1) + 4 + (-2) = 4
Pattern Recognition

In symmetric modulus equations f(|x-a|) = 0, every valid root t generates twin solutions (a+t) and (a-t). The sum of each pair is perfectly 2a. If there are n distinct valid positive roots for t, the sum of all x-roots is exactly n × 2a. Here, n=2, a=1 ⇒ 2 × 2(1) = 4.

Chapter Mix

Class 11 Maths: Quadratic Equations

Reference Study Guides

More Quadratic Equations Previous-Year Questions — Page 6

Q20 jee_main_2024_31_jan_morning Sign of Quadratic Expressions
Let S be the set of positive integral values of a for which (ax² + 2(a + 1)x + 9a + 4)/(x² - 8x + 32) < 0, x in R. Then, the number of elements in S is:
  • A. 1
  • B. 0
  • C. ∞
  • D. 3

Solution

Core Logic

For the denominator x² - 8x + 32, D = 64 - 128 < 0 and a = 1 > 0. Thus, x² - 8x + 32 > 0 x in R.

Step 1: Constraint on Numerator

Since the denominator is always positive, the numerator must be strictly negative for all x in R.

ax² + 2(a + 1)x + 9a + 4 < 0 x in R

This requires a < 0 and D < 0.

Step 2: Conclusion

Since a must be strictly less than 0, there are no positive integral values of a that satisfy the condition. Hence, S is an empty set. Number of elements is 0.

Chapter Mix

Class 11 Maths: Quadratic Equations

More Quadratic Equations Questions — jee_main_2026_21_jan_morning

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JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)