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Express in row reduction to echelon 2x-y+z= -2 3x + 3y + 2 = 3 x+y+z = 2​

User Gmbeard
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Starting with the augmented matrix of the system of equations:

[ 2 -1 1 | -2 ]

[ 3 3 2 | 3 ]

[ 1 1 1 | 2 ]

We can perform row operations to reduce the matrix to row echelon form:

R2 - (3/2)R1 -> R2

[ 2 -1 1 | -2 ]

[ 0 15/2 1/2 | 9 ]

[ 1 1 1 | 2 ]

R3 - (1/2)R1 -> R3

[ 2 -1 1 | -2 ]

[ 0 15/2 1/2 | 9 ]

[ 0 3/2 1/2 | 3 ]

R2 - (1/10)R2 -> R2 and R3 - (1/5)R2 -> R3

[ 2 -1 1 | -2 ]

[ 0 3/2 1/2 | 9/2 ]

[ 0 0 1/3 | 3/2 ]

Finally, we can multiply R3 by 3 and rearrange the rows to obtain the reduced row echelon form:

R3 -> 3R3

[ 2 -1 1 | -2 ]

[ 0 3/2 1/2 | 9/2 ]

[ 0 0 1 | 4.5 ]

R3 -> R3 - (1/2)R2

[ 2 -1 1 | -2 ]

[ 0 3/2 1/2 | 9/2 ]

[ 0 0 1 | 4.5 ]

So the system is equivalent to:

2x - y + z = -2

3/2y + 1/2z = 9/2

z = 4.5

We can solve for y and x in terms of z:

z = 4.5

3/2y + 1/2z = 9/2

3/2y + 1/2(4.5) = 9/2

3/2y = 9/2 - 2.25

3/2y = 1.875

y = 1.25

2x - y + z = -2

2x - 1.25 + 4.5 = -2

2x = -2 - 3.25

2x = -5.25

x = -2.625

Therefore, the solution to the system is:

x = -2.625, y = 1.25, z = 4.5

User Sxalexander
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