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Friday, 9 October

JEE Main 2021 · MathsMultiple choiceSingle correctEasyApplication

JEE Main 3 August 2021, Shift 2, Maths Q64

Question 64 of 90 in this shift, Maths question 4 of 30, Section A.

Let AA be a 3×33\times3 matrix and ∣A∣=−1|A| = -1. A matrix BB is obtained from the matrix AA by applying the following elementary row operations : R2→R2+3R1R_2 \to R_2 + 3R_1 R3→3R3R_3 \to 3R_3 R1→R1−5R3R_1 \to R_1 - 5R_3. Then ∣B∣|B| is equal to :
  1. (1)−27-27
  2. (2)−3-3Official answer
  3. (3)11
  4. (4)1111

Official answer

Option 2

NTA final key.

Chapter
Determinants
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

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.