JEE Main 2021 · MathsNumerical answerNumerical valueMediumMulti-step

JEE Main 17 March 2021, Shift 2, Maths Q90

Question 90 of 90 in this shift, Maths question 30 of 30, Section B.

Let

A=\begin{bmatrix}a & b\\ c & d\end{bmatrix}

and

B=\begin{bmatrix}\alpha\\ \beta\end{bmatrix}\neq\begin{bmatrix}0\\ 0\end{bmatrix}

such that

AB=B

and

a+d=2021

, then the value of

ad-bc

is equal to __________.

Official answer

2020

NTA final key.

Chapter: Matrices
Topic: Cramer's Rule
Idea tested: Eigenvalue-Type Homogeneous Systems

Same topic in other shifts

All Cramer's Rule questions

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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 108 of the 174 JEE Main shifts held from 2017 to 2026.