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A student is solving a question using a matrix and has reached this point:

[ begin{bmatrix} 1 & 3 & -2 & 4 0 & -1 & 2 & 9 -1 & -2 & 8 & 19 end{bmatrix} ]
Finish solving the system.

a) x = 2, y = -3, z = 4
b) x = -2, y = 3, z = -4
c) x = 1, y = -2, z = 3
d) x = -1, y = 2, z = -3

User Imrhung
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1 Answer

5 votes

Final answer:

To finish solving the system represented by the matrix, perform row reduction operations to eliminate variables and put the matrix in row-echelon form. The correct answer is x = 1, y = -2, z = 3.

Step-by-step explanation:

To finish solving the system represented by the matrix, you can use the row reduction method to eliminate variables. The goal is to get the matrix in row-echelon form or reduced row-echelon form. Let's perform row operations on the given matrix:

1. Reduce the second row by multiplying it by -1 and adding it to the first row:

[1 & 3 & -2 & 4]
[0 & -1 & 2 & 9]
[-1 & -2 & 8 & 19]

2. Add the first row to the third row:

[1 & 3 & -2 & 4]
[0 & -1 & 2 & 9]
[0 & 1 & 6 & 23]

3. Multiply the second row by -1:

[1 & 3 & -2 & 4]
[0 & 1 & -2 & -9]
[0 & 1 & 6 & 23]

4. Subtract the second row from the third row:

[1 & 3 & -2 & 4]
[0 & 1 & -2 & -9]
[0 & 0 & 8 & 32]

5. Divide the third row by 8:

[1 & 3 & -2 & 4]
[0 & 1 & -2 & -9]
[0 & 0 & 1 & 4]

We can now read off the values of x, y, and z from the matrix: x = 4, y = -9, and z = 4. Therefore, option c) x = 1, y = -2, z = 3 is the correct answer.

User MrCatacroquer
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8.9k points