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Complex Numbers and Quadratic Equations · Question 33

JEE Main 2026 (Online) 21st January Morning ShiftMCQEasy📈 Topic in 16% papers+4−1
1

If x2 + x + 1 = 0, then the value of (x + 1x )4 + (x2 + 1x2 )4 + (x3 + 1x3 )4 + + (x25 + 1x25 )4 is:

  1. 162
  2. 145
  3. 128
  4. 175

Answer

(2) 145

Solution

x2 + x + 1 = 0 x = or 2, where 3 = 1 and 1 + + 2 = 0.

xn + 1xn = n + 2n

If n is a multiple of 3: n + 2n = 1 + 1 = 2 term = 24 = 16

If n is not a multiple of 3: n + 2n = + 2 = -1 term = (-1)4 = 1

For n = 1 to 25, multiples of 3 are 3, 6, …, 24 8 terms; remaining 17 terms.

Sum = 8 16 + 17 1 = 128 + 17 = 145

Answer: (2)

JEE Main 2026 (Online) 21st January Morning Shift

Keep practising — Complex Numbers and Quadratic Equations

2

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

  1. 3
  2. 1
  3. 4
  4. 5
JEE Main 2026 (Online) 21st January Morning Shift
3

Let and be the roots of the equation x2 + 2ax + (3a + 10) = 0 such that < 1 < . Then the set of all possible values of a is :

  1. (- , -115 ) (5, )
  2. (- , -115 )
  3. (- , -3)
  4. (- , -2) (5, )
JEE Main 2026 (Online) 21st January Evening Shift
4

Let z be the complex number satisfying |z - 5| 3 and having maximum positive principal argument. Then 34 | 5z - 125iz + 16 |2 is equal to:

  1. 20
  2. 26
  3. 12
  4. 16
JEE Main 2026 (Online) 21st January Evening Shift
5

Let be a solution of x2 + x + 1 = 0, and for some a and b in R, bmatrix 4 & a & b bmatrix bmatrix 1 & 16 & 13 \ -1 & -1 & 2 \ -2 & -14 & -8 bmatrix = bmatrix 0 & 0 & 0 bmatrix. If 4 4 + m a + n b = 3, then m + n is equal to

  1. 11
  2. 3
  3. 8
  4. 7
JEE Main 2025 (Online) 8th April Evening Shift
6

The sum of the squares of the roots of |x-2|2 + |x-2| - 2 = 0 and the squares of the roots of x2 - 2|x-3| - 5 = 0, is

  1. 24
  2. 26
  3. 36
  4. 30
JEE Main 2025 (Online) 8th April Evening Shift
7

Let A = \ [0, 2 ] : 1 + 10 Re ( 2 + i - 3i ) = 0 \. Then A 2 is equal to

  1. 214 2
  2. 6 2
  3. 274 2
  4. 8 2
JEE Main 2025 (Online) 8th April Evening Shift
8

Let the set of all values of p R, for which both the roots of the equation x2 - (p + 2)x + (2p + 9) = 0 are negative real numbers, be the interval ( , ]. Then - 2 is equal to

  1. 5
  2. 0
  3. 20
  4. 9
JEE Main 2025 (Online) 7th April Morning Shift
9

Among the statements (S1) : The set \z C - \-i\ : |z| = 1 and z - iz + i is purely real \ contains exactly two elements, and (S2) : The set \z C - \-1\ : |z| = 1 and z - 1z + 1 is purely imaginary \ contains infinitely many elements.

  1. both are incorrect
  2. both are correct
  3. only (S2) is correct
  4. only (S1) is correct
JEE Main 2025 (Online) 7th April Morning Shift
10

If the locus of z C, such that Re ( z-12z+i ) + Re ( z-12 z-i ) = 2, is a circle of radius r and center (a, b), then 15abr2 is equal to :

  1. 16
  2. 24
  3. 12
  4. 18
JEE Main 2025 (Online) 7th April Evening Shift
11

The number of real roots of the equation x|x-2| + 3|x-3| + 1 = 0 is :

  1. 4
  2. 3
  3. 2
  4. 1
JEE Main 2025 (Online) 7th April Evening Shift

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