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Friday, 9 October

JEE Main 2026 · MathsMultiple choiceSingle correctHardMulti-step

JEE Main 8 April 2026, Shift 2, Maths Q4

Question 4 of 75 in this shift, Maths question 4 of 25, Section A.

Let A=[α12230045]A = \begin{bmatrix} \alpha & 1 & 2 \\ 2 & 3 & 0 \\ 0 & 4 & 5 \end{bmatrix} and B=[1000−5α004α−2α]+adj(A)B = \begin{bmatrix} 1 & 0 & 0 \\ 0 & -5\alpha & 0 \\ 0 & 4\alpha & -2\alpha \end{bmatrix} + \mathrm{adj}(A). If det⁡(B)=66\det(B) = 66, then det⁡(adj(A))\det(\mathrm{adj}(A)) equals :
  1. (1)289
  2. (2)361
  3. (3)441Official answer
  4. (4)529

Official answer

Option 3

NTA final key.

Chapter
Determinants
Topic
Matrix Inverse
Idea tested
Cofactor Matrix and Adjoint

Same idea in other shifts

Asked 2× in all
  1. 2 Apr 2017 (offline) · Q64If A=[2−3−41]A=\begin{bmatrix}2&-3\\-4&1\end{bmatrix}, then adj(3A2+12A)\mathrm{adj}(3A^2+12A) is equal to :MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.