System of Linear Equations

Definition

A system of linear equations is a collection of two or more linear equations that share the same set of variables. These equations must be solved simultaneously to find the values of the variables that satisfy all the equations in the system.

5 Must Know Facts For Your Next Test

1. The solution to a system of linear equations is the set of values for the variables that satisfies all the equations in the system.
2. Systems of linear equations can have one unique solution, no solution, or infinitely many solutions, depending on the relationships between the equations.
3. Graphically, a system of linear equations can be represented by a set of lines in a coordinate plane, and the solution is the point of intersection of these lines.
4. The number of equations in a system must be equal to the number of variables for the system to have a unique solution.
5. Augmented matrices and Gaussian elimination are powerful tools for solving systems of linear equations, especially when the number of equations and variables is large.

Review Questions

• Explain how the graphical representation of a system of linear equations can be used to determine the number and nature of the solutions.
  • The graphical representation of a system of linear equations shows the lines corresponding to each equation in the coordinate plane. If the lines intersect at a single point, the system has a unique solution, which is the coordinates of that point. If the lines are parallel, the system has no solution. If the lines are the same, the system has infinitely many solutions, as any point on the line satisfies the equations.
• Describe the role of the augmented matrix in solving a system of linear equations, and explain how Gaussian elimination is used to transform the augmented matrix into row echelon form.
  • The augmented matrix combines the coefficients of the variables and the constants from a system of linear equations into a single matrix. Gaussian elimination is a method used to transform the augmented matrix into row echelon form, which allows for the identification of the solution. This process involves performing a series of row operations, such as row swapping, row scaling, and row addition, to eliminate the variables and isolate the solutions.
• Analyze the conditions under which a system of linear equations will have no solution, a unique solution, or infinitely many solutions, and explain the implications of each case.
  • A system of linear equations will have no solution if the equations are inconsistent, meaning they represent parallel lines that do not intersect. This can occur if the equations are linearly independent, and the system is overdetermined. A system will have a unique solution if the equations are linearly independent and the system is determined, meaning the number of equations is equal to the number of variables. A system will have infinitely many solutions if the equations are linearly dependent, and the system is underdetermined, meaning the number of equations is less than the number of variables. Understanding these conditions is crucial for determining the feasibility and nature of the solutions to a system of linear equations.

Related terms

Linear Equation:

A linear equation is an equation in which each term is either a constant or the product of a constant and a single variable raised to the first power.

Augmented Matrix: An augmented matrix is a matrix that combines the coefficients of the variables and the constants from a system of linear equations into a single matrix.

Gaussian Elimination: Gaussian elimination is a method used to solve a system of linear equations by transforming the augmented matrix into row echelon form, which allows for the identification of the solution.