Is Matrix A Invertible? Solving Linear System with Gaussian Elimination

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SUMMARY

The discussion centers on the invertibility of a 6x6 matrix A in the context of solving a linear system Ax = c using Gaussian elimination. It is established that if the solution can be expressed as x = x0 + a1x1 + a2x2, where a1 and a2 are arbitrary, then A cannot be invertible. This is because an invertible matrix must yield a unique solution, contradicting the presence of infinitely many solutions indicated by the arbitrary coefficients.

PREREQUISITES
  • Understanding of Gaussian elimination
  • Knowledge of linear algebra concepts, specifically matrix invertibility
  • Familiarity with the properties of linear systems
  • Basic proficiency in vector notation
NEXT STEPS
  • Study the properties of invertible matrices in linear algebra
  • Learn about the implications of unique versus infinite solutions in linear systems
  • Explore the process of Gaussian elimination in detail
  • Investigate the relationship between matrix rank and invertibility
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Students studying linear algebra, educators teaching matrix theory, and anyone interested in understanding the conditions for matrix invertibility and solving linear systems.

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Homework Statement



Suppose that Gaussian Elimination gives the soluiton of a Linear System Ax=c as x = x0 + a1x1 + a2x2, where A is a 6X6 matrix and a1 and a2 are arbitrary. Is the matrix A invertible? Explain


The Attempt at a Solution



I simply explained that due to properties of an invertible matrix, Ax=c must have exactly one solution but if a1 and 2 are arbitrary, then x = x0 + a1x1 + a2x2 has infinitely many solutions and A cannot be invertible

does anyone agree with this answer and if not, any advice on how to start the problem would be great appreciated :redface: thanks a lot!
 
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I'm assuming that x0, x1, and x2 are vectors. Your reasoning looks fine to me. If A had been invertible then you would have gotten a unique solution, which could be written as x = A-1c.
 

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