Solve System of Equations: Find x, y, z & l1, l2, l3

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Discussion Overview

The discussion revolves around solving a system of equations involving both algebraic expressions and electrical circuit equations. Participants seek assistance in applying methods such as Gaussian Elimination to find the values of the variables involved.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant presents two systems of equations and provides what they believe are the correct solutions for the variables.
  • Another participant emphasizes the need for the original poster to share their attempted methods to determine the appropriate solving technique.
  • A participant expresses difficulty with the Gaussian Elimination method and seeks clarification on the steps involved.
  • Another participant mentions confusion regarding the steps in solving the second problem, which they found in an Electricians Book.
  • A participant suggests that both problems can be approached using an augmented matrix and Gaussian Elimination, outlining the elementary row operations involved.
  • One participant notes that the question has been answered in another forum to avoid duplication of effort.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach to solve the equations, and multiple methods are discussed without resolution on which is most appropriate.

Contextual Notes

Some participants express uncertainty about the steps in Gaussian Elimination and the application of methods to the specific problems presented. There is also a mention of potential confusion stemming from the source material for the second problem.

haydenmwht
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I am new to this site and am not all that great at math but am trying to grow. I can't figure out how to work these equations.1) x + y + z = 15
5x - z = 18
4y + z = 19In this one I need to solve for the variables. the answers for x, y, z are 5,3,7

2) l1 + l3 = l2
5.2l1 - 3.25l2 = (-12.35)
3.25l2 - 2.61l3 = 64.35The answers for l1, l2, & l3 are 17A, 31A, & 14A. Thanks for any help!
 
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haydenmwht said:
I am new to this site and am not all that great at math but am trying to grow. I can't figure out how to work these equations.1) x + y + z = 15
5x - z = 18
4y + z = 19In this one I need to solve for the variables. the answers for x, y, z are 5,3,7

2) l1 + l3 = l2
5.2l1 - 3.25l2 = (-12.35)
3.25l2 - 2.61l3 = 64.35The answers for l1, l2, & l3 are 17A, 31A, & 14A. Thanks for any help!

There are many ways to solve these problems, and unless you show us what you have tried, we have no way of knowing which method is appropriate for the purposes of your course.
 
I am trying to use the Gaussian Elimination method but I am struggling in the exact steps going through them. I don't mean to sound dumb.
 
I am mainly struggling with problem 2. I found this in an Electricians Book and am confused on the steps for their answer. I'll figure it out soon I'm sure but am still confused.
 
Hi haydenmwht,

Both problems can be done by setting up an augmented matrix and applying Gaussian Elimination. I'm assuming you are confused about the process of applying GE? From wikipedia, the elementary row operations are the following:

  • Type 1: Swap the positions of two rows.
  • Type 2: Multiply a row by a nonzero scalar.
  • Type 3: Add to one row a scalar multiple of another.

There are no hard and fast rules to GE...just some better or worse methods. :)
 
Last edited:
Hi everyone,

I just wanted to point out in order to prevent any duplication of effort, that this question has been answered elsewhere.

Help with Problem - Math Help Forum
 

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