Solving a System of Equations with Gaussian Elimination

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SUMMARY

The discussion focuses on solving a system of equations using Gaussian elimination, specifically for the equations involving a parameter 'a'. The equations are: ax1 + 2x2 + ax3 = 5a, x1 + 2x2 + (2-a)x3 = 5, and 3x1 + (a+2)x2 + 6x3 = 15. Participants suggest applying Gaussian elimination by manipulating the coefficient matrix to achieve row-echelon form, with specific operations outlined for eliminating variables. It is noted that dividing by 'a' assumes that 'a' is not equal to zero, which is a critical consideration in the solution process.

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  • Understanding of Gaussian elimination techniques
  • Familiarity with systems of linear equations
  • Knowledge of matrix operations
  • Basic algebra involving parameters
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Homework Statement


Show that the following equations can be solved for any a:
ax1 + 2x2 + ax3 = 5a
x1 + 2x2 + (2-a)x3 = 5
3x1 + (a+2)x2 + 6x3 = 15

2. The attempt at a solution
I thought I would do gaussian elimination to get it into reduced form (in a coefficient matrix), and see where I can go from there. But I don't know how to do Gaussian elimination because the coefficient of a certrain x1 is a...

Can anybody give a hint?
 
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Just use Gaussian elimination. For starters, add row 1 to -a times row 2, and add -3 times row 1 to a times row 3. That will eliminate the first entries in the 2nd and 3rd rows. Continue until you get the system in row-echelon form.

Alternatively, you can divide row 1 by a, but in doing so, you are tacitly assuming that a != 0.
 

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