Finite Math Examples

$x + 6 y + 4 z = - 3$ , $2 x + 9 y - z = - 12$ , $3 x + 19 y + 15 z = - 7$

Step 1

Move all terms not containing $x$ to the right side of the equation.

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Step 1.1

Subtract $6 y$ from both sides of the equation.

$x + 4 z = - 3 - 6 y$

$2 x + 9 y - z = - 12$

$3 x + 19 y + 15 z = - 7$

Step 1.2

Subtract $4 z$ from both sides of the equation.

$x = - 3 - 6 y - 4 z$

$2 x + 9 y - z = - 12$

$3 x + 19 y + 15 z = - 7$

$x = - 3 - 6 y - 4 z$

$2 x + 9 y - z = - 12$

$3 x + 19 y + 15 z = - 7$

Step 2

Replace all occurrences of $x$ with $- 3 - 6 y - 4 z$ in each equation.

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Step 2.1

Replace all occurrences of $x$ in $2 x + 9 y - z = - 12$ with $- 3 - 6 y - 4 z$ .

$2 (- 3 - 6 y - 4 z) + 9 y - z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

Step 2.2

Simplify the left side.

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Step 2.2.1

Simplify $2 (- 3 - 6 y - 4 z) + 9 y - z$ .

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Step 2.2.1.1

Simplify each term.

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Step 2.2.1.1.1

Apply the distributive property.

$2 \cdot - 3 + 2 (- 6 y) + 2 (- 4 z) + 9 y - z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

Step 2.2.1.1.2

Simplify.

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Step 2.2.1.1.2.1

Multiply $2$ by $- 3$ .

$- 6 + 2 (- 6 y) + 2 (- 4 z) + 9 y - z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

Step 2.2.1.1.2.2

Multiply $- 6$ by $2$ .

$- 6 - 12 y + 2 (- 4 z) + 9 y - z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

Step 2.2.1.1.2.3

Multiply $- 4$ by $2$ .

$- 6 - 12 y - 8 z + 9 y - z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

$- 6 - 12 y - 8 z + 9 y - z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

$- 6 - 12 y - 8 z + 9 y - z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

Step 2.2.1.2

Simplify by adding terms.

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Step 2.2.1.2.1

Add $- 12 y$ and $9 y$ .

$- 6 - 3 y - 8 z - z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

Step 2.2.1.2.2

Subtract $z$ from $- 8 z$ .

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$3 x + 19 y + 15 z = - 7$

Step 2.3

Replace all occurrences of $x$ in $3 x + 19 y + 15 z = - 7$ with $- 3 - 6 y - 4 z$ .

$3 (- 3 - 6 y - 4 z) + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 2.4

Simplify the left side.

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Step 2.4.1

Simplify $3 (- 3 - 6 y - 4 z) + 19 y + 15 z$ .

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Step 2.4.1.1

Simplify each term.

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Step 2.4.1.1.1

Apply the distributive property.

$3 \cdot - 3 + 3 (- 6 y) + 3 (- 4 z) + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 2.4.1.1.2

Simplify.

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Step 2.4.1.1.2.1

Multiply $3$ by $- 3$ .

$- 9 + 3 (- 6 y) + 3 (- 4 z) + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 2.4.1.1.2.2

Multiply $- 6$ by $3$ .

$- 9 - 18 y + 3 (- 4 z) + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 2.4.1.1.2.3

Multiply $- 4$ by $3$ .

$- 9 - 18 y - 12 z + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$- 9 - 18 y - 12 z + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$- 9 - 18 y - 12 z + 19 y + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 2.4.1.2

Simplify by adding terms.

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Step 2.4.1.2.1

Add $- 18 y$ and $19 y$ .

$- 9 + y - 12 z + 15 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 2.4.1.2.2

Add $- 12 z$ and $15 z$ .

$- 9 + y + 3 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$- 9 + y + 3 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$- 9 + y + 3 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$- 9 + y + 3 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$- 9 + y + 3 z = - 7$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 3

Move all terms not containing $y$ to the right side of the equation.

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Step 3.1

Add $9$ to both sides of the equation.

$y + 3 z = - 7 + 9$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 3.2

Subtract $3 z$ from both sides of the equation.

$y = - 7 + 9 - 3 z$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 3.3

Add $- 7$ and $9$ .

$y = 2 - 3 z$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

$y = 2 - 3 z$

$- 6 - 3 y - 9 z = - 12$

$x = - 3 - 6 y - 4 z$

Step 4

Replace all occurrences of $y$ with $2 - 3 z$ in each equation.

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Step 4.1

Replace all occurrences of $y$ in $- 6 - 3 y - 9 z = - 12$ with $2 - 3 z$ .

$- 6 - 3 (2 - 3 z) - 9 z = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

Step 4.2

Simplify the left side.

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Step 4.2.1

Simplify $- 6 - 3 (2 - 3 z) - 9 z$ .

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Step 4.2.1.1

Simplify each term.

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Step 4.2.1.1.1

Apply the distributive property.

$- 6 - 3 \cdot 2 - 3 (- 3 z) - 9 z = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

Step 4.2.1.1.2

Multiply $- 3$ by $2$ .

$- 6 - 6 - 3 (- 3 z) - 9 z = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

Step 4.2.1.1.3

Multiply $- 3$ by $- 3$ .

$- 6 - 6 + 9 z - 9 z = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

$- 6 - 6 + 9 z - 9 z = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

Step 4.2.1.2

Simplify by adding terms.

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Step 4.2.1.2.1

Combine the opposite terms in $- 6 - 6 + 9 z - 9 z$ .

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Step 4.2.1.2.1.1

Subtract $9 z$ from $9 z$ .

$- 6 - 6 + 0 = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

Step 4.2.1.2.1.2

Add $- 6 - 6$ and $0$ .

$- 6 - 6 = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

$- 6 - 6 = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

Step 4.2.1.2.2

Subtract $6$ from $- 6$ .

$- 12 = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

$- 12 = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

$- 12 = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

$- 12 = - 12$

$y = 2 - 3 z$

$x = - 3 - 6 y - 4 z$

Step 4.3

Replace all occurrences of $y$ in $x = - 3 - 6 y - 4 z$ with $2 - 3 z$ .

$x = - 3 - 6 (2 - 3 z) - 4 z$

$- 12 = - 12$

$y = 2 - 3 z$

Step 4.4

Simplify the right side.

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Step 4.4.1

Simplify $- 3 - 6 (2 - 3 z) - 4 z$ .

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Step 4.4.1.1

Simplify each term.

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Step 4.4.1.1.1

Apply the distributive property.

$x = - 3 - 6 \cdot 2 - 6 (- 3 z) - 4 z$

$- 12 = - 12$

$y = 2 - 3 z$

Step 4.4.1.1.2

Multiply $- 6$ by $2$ .

$x = - 3 - 12 - 6 (- 3 z) - 4 z$

$- 12 = - 12$

$y = 2 - 3 z$

Step 4.4.1.1.3

Multiply $- 3$ by $- 6$ .

$x = - 3 - 12 + 18 z - 4 z$

$- 12 = - 12$

$y = 2 - 3 z$

$x = - 3 - 12 + 18 z - 4 z$

$- 12 = - 12$

$y = 2 - 3 z$

Step 4.4.1.2

Simplify by adding terms.

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Step 4.4.1.2.1

Subtract $12$ from $- 3$ .

$x = - 15 + 18 z - 4 z$

$- 12 = - 12$

$y = 2 - 3 z$

Step 4.4.1.2.2

Subtract $4 z$ from $18 z$ .

$x = - 15 + 14 z$

$- 12 = - 12$

$y = 2 - 3 z$

$x = - 15 + 14 z$

$- 12 = - 12$

$y = 2 - 3 z$

$x = - 15 + 14 z$

$- 12 = - 12$

$y = 2 - 3 z$

$x = - 15 + 14 z$

$- 12 = - 12$

$y = 2 - 3 z$

$x = - 15 + 14 z$

$- 12 = - 12$

$y = 2 - 3 z$

Step 5

Remove any equations from the system that are always true.

$x = - 15 + 14 z$

$y = 2 - 3 z$