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Ch. 6 - Matrices and Determinants
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
7장, 문제 9

In Exercises 8–11, use Gaussian elimination to find the complete solution to each system, or show that none exists.

검증된 단계별 안내
1
Write the given system of linear equations in augmented matrix form. The augmented matrix combines the coefficients of the variables and the constants from the equations into a single matrix.
Use row operations (row swapping, scaling a row by a nonzero constant, or adding/subtracting multiples of one row to another) to transform the augmented matrix into row-echelon form. The goal is to create zeros below the pivot positions (leading entries in each row).
Continue applying row operations to transform the matrix into reduced row-echelon form (RREF). In RREF, each pivot is 1, and all other entries in the pivot's column are 0.
Interpret the resulting matrix. If the system has a unique solution, the RREF will clearly show the values of the variables. If there are free variables (columns without pivots), express the solution in terms of these free variables. If a row in the matrix corresponds to an inconsistent equation (e.g., 0 = 1), conclude that no solution exists.
Write the complete solution, if it exists, in terms of the variables. If there are free variables, express the solution as a parametric equation. If no solution exists, state that the system is inconsistent.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Gaussian Elimination

Gaussian elimination is a systematic method for solving systems of linear equations. It involves transforming the system's augmented matrix into row echelon form using a series of row operations, which include swapping rows, multiplying a row by a non-zero scalar, and adding or subtracting rows. This process simplifies the equations, making it easier to find solutions or determine if no solution exists.
추천 영상:
가이드 코스
6:48
Solving Systems of Equations - Elimination

Row Echelon Form

Row echelon form is a specific arrangement of a matrix where all non-zero rows are above any rows of all zeros, and the leading coefficient of each non-zero row (the first non-zero number from the left) is to the right of the leading coefficient of the previous row. This form is crucial in Gaussian elimination as it allows for back substitution to find the values of the variables in a linear system.
추천 영상:
가이드 코스
7:54
Solving Systems of Equations - Matrices (Row-Echelon Form)

Existence of Solutions

In the context of linear systems, the existence of solutions refers to whether a system has one unique solution, infinitely many solutions, or no solution at all. This can be determined during the Gaussian elimination process by examining the final row echelon form of the augmented matrix. If a row leads to a contradiction (like 0 = 1), the system has no solution; if there are free variables, it indicates infinitely many solutions.
추천 영상:
5:14
Probability of Non-Mutually Exclusive Events