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-2x-3y+z=-6
x=y-z=5
7x=8y-6z=31

1 Answer

4 votes

Answer:

{y,z,x} = {1/3,-13/3,1/3}

Explanation:

Step by Step Solution:

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System of Linear Equations entered :

[1] -2y-3y+z=-6

[2] x+y-z=5

[3] 7x+8y-6z=31

Equations Simplified or Rearranged :

[1] -5y + z = -6

[2] y - z + x = 5

[3] 8y - 6z + 7x = 31

Solve by Substitution :

// Solve equation [2] for the variable x

[2] x = -y + z + 5

// Plug this in for variable x in equation [3]

[3] 8y - 6z + 7•(-y +z +5) = 31

[3] y + z = -4

// Solve equation [3] for the variable z

[3] z = -y - 4

// Plug this in for variable z in equation [1]

[1] -5y + (-y -4) = -6

[1] -6y = -2

// Solve equation [1] for the variable y

[1] 6y = 2

[1] y = 1/3

// By now we know this much :

y = 1/3

z = -y-4

x = -y+z+5

// Use the y value to solve for z

z = -(1/3)-4 = -13/3

// Use the y and z values to solve for x

x = -(1/3)+(-13/3)+5 = 1/3

Solution :

{y,z,x} = {1/3,-13/3,1/3}

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