The system of equations are \"\".

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Use the elimination method to make a system of two equations in two variables.

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The two equations 1 and 2 contains opposite coefficient of z - variable.

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Write the equations 1 and 2 in column form and add the corresponding columns to eliminate z - variable.

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The resultant equation is taken as fourth equation : 3x + y = 10.

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The two equations 2 and 3 contains same coefficient of z - variable.

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Write the equations 2 and 3 in column form and subtract the corresponding columns to eliminate z - variable.

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The resultant equation is taken as fifth equation : 3x + 2y = 11.

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Solve the system of two equations with two variables.

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The two equations 4 and 5 contains same coefficient of x - variable.

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Write the equations 4 and 5 in column form and subtract the corresponding columns to eliminate x - variable.

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\"\".

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The resultant equation is - y = - 1 ----> y = 1.

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Use one of the equation with two variables (Equation: 4 or 5) to solve for x.

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The fourth equation: 3x + y = 10.

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3x + (1) = 10

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3x = 9

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x = 3.

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Solve for z using one of the original equations with three variables.

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The second equation: 2x - y + z = 7.

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2(3) - (1) + z = 7

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5 + z = 7

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z = 2.

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The solution (x, y, z) = (3, 1, 2).