JEE Main 2021 · MathsMultiple choiceSingle correctMediumApplication

JEE Main 26 February 2021, Shift 2, Maths Q74

Question 74 of 90 in this shift, Maths question 14 of 30, Section A.

Consider the following system of equations :

x+2y-3z=a

2x+6y-11z=b

x-2y+7z=c

, where a, b and c are real constants. Then the system of equations :

(1)has a unique solution for all a, b and c
(2)has a unique solution when $5a=2b+c$
(3)has infinite number of solutions when $5a=2b+c$ Official answer
(4)has no solution for all a, b and c

Official answer

Option 3

NTA final key.

Chapter: Determinants
Topic: Cramer's Rule
Idea tested: Condition for Infinite Solutions

Same idea in other shifts

Asked 25× in all

2 Apr 2026, Shift 2 · Q3If the system of equations $x + 5y + 6z = 4,$ $2x + 3y + 4z = 7,$ $x + 6y + az = b$ has infinitely many solutions, then the point $(a, b)$ …MediumSingle correct
4 Apr 2026, Shift 2 · Q3If the system of equations: $x+y+z=5$ $x+2y+3z=9$ $x+3y+\lambda z=\mu$ has infinitely many solutions, then the value of $\lambda+\mu$ is:EasySingle correct
8 Apr 2026, Shift 2 · Q3If the system of linear equations : $x + y + z = 6$ , $x + 2y + 5z = 10$ , $2x + 3y + \lambda z = \mu$ has infinitely many solutions, then…EasySingle correct
2 Apr 2025, Shift 1 · Q20If the system of linear equations $3x+y+\beta z=3$ $2x+\alpha y-z=-3$ $x+2y+z=4$ has infinitely many solutions, then the value of…MediumSingle correct
5 Apr 2024, Shift 1 · Q4If the system of equations $11x+y+\lambda z=-5$ $2x+3y+5z=3$ $8x-19y-39z=\mu$ has infinitely many solutions, then $\lambda^4-\mu$ is equal…MediumSingle correct
5 Apr 2024, Shift 2 · Q4The values of $m, n$ , for which the system of equations $x+y+z=4$ , $2x+5y+5z=17$ , $x+2y+mz=n$ has infinitely many solutions, satisfy the…MediumSingle correct
6 Apr 2024, Shift 2 · Q22If the system of equations $2x+7y+\lambda z=3$ $3x+2y+5z=4$ $x+\mu y+32z=-1$ has infinitely many solutions, then $(\lambda-\mu)$ is equal…MediumNumerical value
8 Apr 2024, Shift 2 · Q3If the system of equations $x + 4y - z = \lambda$ , $7x + 9y + \mu z = -3$ , $5x + y + 2z = -1$ has infinitely many solutions, then…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 108 of the 174 JEE Main shifts held from 2017 to 2026.