Chapter 4: Problem 37
Solve each system using the Gauss-Jordan elimination method. $$ \begin{aligned} x+y &=-6 \\ 3 y &=6 \end{aligned} $$
Short Answer
Expert verified
x = -8, y = 2
Step by step solution
01
- Write the system of equations in augmented matrix form
The given system of equations is: 1. \[ x + y = -6 \] 2. \[ 3y = 6 \]Rewrite this system as an augmented matrix:
02
- Create the augmented matrix
The augmented matrix for the system is:\[ \begin{bmatrix} 1 & 1 & | & -6 \ 0 & 3 & | & 6 ewline \rightarrow \begin{bmatrix} 1 & 1 & | & -6 \ 0 & 3 & | & 6 \end{bmatrix} \]
03
- Simplify the second row
Divide the entire second row by 3 to make the coefficient of y equal to 1:\[ \begin{bmatrix} 1 & 1 & | & -6 \ 0 & 1 & | & 2 \end{bmatrix} \]
04
- Eliminate y from the first row
Subtract the second row from the first row to eliminate the y-term from the first row: \[ (1, 1, |, -6) - (0, 1, |, 2) \rightarrow (1, 0, |, -8) \] Resulting matrix is:\[ \begin{bmatrix} 1 & 0 & | & -8 \ 0 & 1 & | & 2 \ \rightarrow \begin{bmatrix} 1 & 0 & | & -8 \ 0 & 1 & | & 2 \ \rightarrow \begin{bmatrix} 1 & 1 & | & -6 \ 0 & 1 & | & 2 \ \rightarrow 1 & 1 & | & -6 \ 0 & 3 & | & 6 \ -1 & -1 & | & -6 \ 0 & 1 & | & 1ith \ } \end{bmatrix} \]
05
- Write the solution
The resulting augmented matrix from Step 4 represents the system of equations:x = -8y = 2Thus, the solution to the system of equations is \( x = -8 \) and \( y = 2 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Augmented Matrix
When solving a system of linear equations, it is quite helpful to use an augmented matrix. An augmented matrix combines the coefficients of the variables and the constants from the equations into a compact form. This makes operations like row reduction easier and more organized.
An augmented matrix for a system of linear equations looks like this:
\[ \begin{bmatrix} a_1 & b_1 & | & c_1 ewline a_2 & b_2 & | & c_2 ewline \text{...} & ... & | & \text{...} ewline a_n & b_n & | & c_n ewline \right] \] Here, \(\begin{bmatrix} a_1 & b_1 ewline a_2 & b_2 ewline ... & ... ewline a_n & b_n \right]\) represents the matrix of coefficients for the variables, and \[ \begin{pmatrix} c_1 ewline c_2 ewline \text{...} ewline c_n \right] \] represents the constants on the right side of the equations. This format neatly arranges the information, so we can carry out row operations effortlessly.
An augmented matrix for a system of linear equations looks like this:
\[ \begin{bmatrix} a_1 & b_1 & | & c_1 ewline a_2 & b_2 & | & c_2 ewline \text{...} & ... & | & \text{...} ewline a_n & b_n & | & c_n ewline \right] \] Here, \(\begin{bmatrix} a_1 & b_1 ewline a_2 & b_2 ewline ... & ... ewline a_n & b_n \right]\) represents the matrix of coefficients for the variables, and \[ \begin{pmatrix} c_1 ewline c_2 ewline \text{...} ewline c_n \right] \] represents the constants on the right side of the equations. This format neatly arranges the information, so we can carry out row operations effortlessly.
System of Linear Equations
A system of linear equations is essentially a set of equations with multiple variables. Each equation adds a constraint, or rule, that the variables need to satisfy. For example, consider the following system:
\[ \begin{aligned} x + y &= -6 \ 3y &= 6 \right] \]
In this system, we have two equations with two variables, x and y. The goal is to determine the values of x and y that satisfy both equations simultaneously.
Systems of linear equations can have one solution, no solution, or infinitely many solutions depending on the relationships between the equations. Solving a system can be done using various methods, including substitution, elimination, and matrix operations like Gauss-Jordan elimination.
\[ \begin{aligned} x + y &= -6 \ 3y &= 6 \right] \]
In this system, we have two equations with two variables, x and y. The goal is to determine the values of x and y that satisfy both equations simultaneously.
Systems of linear equations can have one solution, no solution, or infinitely many solutions depending on the relationships between the equations. Solving a system can be done using various methods, including substitution, elimination, and matrix operations like Gauss-Jordan elimination.
Linear Algebra
Linear algebra offers a structured way to handle systems of linear equations and numerous other concepts related to vector spaces and linear mappings. It's a fundamental area of mathematics with applications in many fields including physics, engineering, computer science, and economics.
Key concepts in linear algebra include:
For solving systems of linear equations, matrices are indispensable. Methods like Gauss-Jordan elimination utilize matrix operations to simplify systems into a form where the solutions are easily recognizable. By mastering linear algebra, one gains powerful tools for both theoretical and practical problem-solving in diverse areas.
Key concepts in linear algebra include:
- Vectors and vector spaces
- Matrices and matrix operations
- Determinants
- Eigenvalues and eigenvectors
For solving systems of linear equations, matrices are indispensable. Methods like Gauss-Jordan elimination utilize matrix operations to simplify systems into a form where the solutions are easily recognizable. By mastering linear algebra, one gains powerful tools for both theoretical and practical problem-solving in diverse areas.