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Matrices

Question
CBSEENMA12036122

If S is the set of distinct values of 'b' for which the following system of linear equations
x + y + z = 1
x + ay + z = 1
ax + by + z = 0
has no solution, then S is

  • a singleton

  • an empty set

  • an infinite set

  • a finite set containing two or more elements

Solution

A.

a singleton

straight D space equals space open vertical bar table row 1 1 1 row 1 straight a 1 row straight a straight b 1 end table close vertical bar space equals space 0
rightwards double arrow straight a space equals space 1
and space at space straight a space equals space 1
straight D subscript 1 space equals straight D subscript 2 space equals space straight D subscript 3 space equals space 0

but at a = 1 and b =1
First two equations are x +y+ z =1
and third equations is x + y +z = 0
⇒ There is no solution
therefore, b = {1}
⇒ it is a singleton set