48.9k views
5 votes
Judge if the following linear system of equations has solutions or not. If it has, find the solutions only by Gauss elimination.

A. 2x₁ + 5x₂ + 4x₃ + 5x₄ = -5
B. 2x₁ + 3x₂ + 3x₃ - 1x₄ = 7
C. 2x₁ + 3x₂ + 3x₃ + 4x₄ = 3
D. 2x₁ - x₂ + 5x₃ - 4x₄ = 21

1 Answer

3 votes

Final answer:

The linear system of equations does not have a solution, indicated by a contradiction in the Gauss elimination process, where an abnormal row suggests that a solution is not possible.

Step-by-step explanation:

In order to assess the solvability of the linear system of equations and employ Gauss elimination to find solutions, the system is initially transformed into an augmented matrix:

2 5 4 5 | -5

2 3 3 -1 | 7

2 3 3 4 | 3

2 -1 5 -4 | 21

Initiating the Gauss elimination, the first column is already set as a pivot (2). Subsequent steps involve subtracting the first row from the second, third, and fourth rows to yield:

2 5 4 5 | -5

0 -2 -1 -6 | 12

0 -2 -1 -1 | 8

0 -6 1 -9 | 26

Continuing the process, the second column's pivot is chosen as -2, and further operations lead to:

2 5 4 5 | -5

0 -2 -1 -6 | 12

0 0 0 -7 | 20

0 0 -2 -27 | 62

For the third column, the number -2 can be our pivot for the fourth row. We can change the fourth row by adding the third row to it:

2 5 4 5 | -5

0 -2 -1 -6 | 12

0 0 0 -7 | 20

0 0 -2 -34 | 82

However, we encounter an abnormal row which implies a contradiction (0 = 82), hence, the original system has no solution.

User Chetan Shirke
by
8.8k points