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Solve the matrix
x+y-z=3
2x+3y+z=10
3x-y-7z=1

1 Answer

2 votes
The system of linear equations can be written in matrix form as AX = B, where:

A = [1 1 -1
2 3 1
3 -1 -7]

X = [x
y
z]

B = [3
10
1]

We can use matrix elimination or Gaussian elimination to solve for X:

Step 1: Subtract 2 times the first row from the second row:

A = [1 1 -1
0 -1 3
3 -1 -7]

B = [3
4
1]

Step 2: Subtract 3 times the first row from the third row:

A = [1 1 -1
0 -1 3
0 -4 -20]

B = [3
4
-8]

Step 3: Divide the second row by -1:

A = [1 1 -1
0 1 -3
0 -4 -20]

B = [3
-4
-8]

Step 4: Subtract the second row from the third row:

A = [1 1 -1
0 1 -3
0 0 -16]

B = [3
-4
-12]

Step 5: Divide the third row by -16:

A = [1 1 -1
0 1 -3
0 0 1]

B = [3
-4
12/16]

Step 6: Subtract -3 times the second row from the first row:

A = [1 0 4
0 1 -3
0 0 1]

B = [15/4
-4
12/16]

Step 7: Solve for x by multiplying the first row by 4:

A = [1 0 4
0 1 -3
0 0 1]

B = [3
-4
12/16]

X = [3
-4
3/4]

So the solution to the system of linear equations is X = [3, -4, 3/4].
User Monsignor
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