Finite Math Examples

$2 x + 9 y - 5 z = 0$ , $7 x - y + 6 z = 1$ , $9 x + 8 y + z = 1$

Step 1

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

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Step 1.1

Subtract $9 x$ from both sides of the equation.

$8 y + z = 1 - 9 x$

$2 x + 9 y - 5 z = 0$

$7 x - y + 6 z = 1$

Step 1.2

Subtract $8 y$ from both sides of the equation.

$z = 1 - 9 x - 8 y$

$2 x + 9 y - 5 z = 0$

$7 x - y + 6 z = 1$

$z = 1 - 9 x - 8 y$

$2 x + 9 y - 5 z = 0$

$7 x - y + 6 z = 1$

Step 2

Replace all occurrences of $z$ with $1 - 9 x - 8 y$ in each equation.

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Step 2.1

Replace all occurrences of $z$ in $2 x + 9 y - 5 z = 0$ with $1 - 9 x - 8 y$ .

$2 x + 9 y - 5 (1 - 9 x - 8 y) = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

Step 2.2

Simplify the left side.

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Step 2.2.1

Simplify $2 x + 9 y - 5 (1 - 9 x - 8 y)$ .

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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.

$2 x + 9 y - 5 \cdot 1 - 5 (- 9 x) - 5 (- 8 y) = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

Step 2.2.1.1.2

Simplify.

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Step 2.2.1.1.2.1

Multiply $- 5$ by $1$ .

$2 x + 9 y - 5 - 5 (- 9 x) - 5 (- 8 y) = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

Step 2.2.1.1.2.2

Multiply $- 9$ by $- 5$ .

$2 x + 9 y - 5 + 45 x - 5 (- 8 y) = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

Step 2.2.1.1.2.3

Multiply $- 8$ by $- 5$ .

$2 x + 9 y - 5 + 45 x + 40 y = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

$2 x + 9 y - 5 + 45 x + 40 y = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

$2 x + 9 y - 5 + 45 x + 40 y = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

Step 2.2.1.2

Simplify by adding terms.

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Step 2.2.1.2.1

Add $2 x$ and $45 x$ .

$47 x + 9 y - 5 + 40 y = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

Step 2.2.1.2.2

Add $9 y$ and $40 y$ .

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 z = 1$

Step 2.3

Replace all occurrences of $z$ in $7 x - y + 6 z = 1$ with $1 - 9 x - 8 y$ .

$7 x - y + 6 (1 - 9 x - 8 y) = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 2.4

Simplify the left side.

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Step 2.4.1

Simplify $7 x - y + 6 (1 - 9 x - 8 y)$ .

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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.

$7 x - y + 6 \cdot 1 + 6 (- 9 x) + 6 (- 8 y) = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 2.4.1.1.2

Simplify.

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Step 2.4.1.1.2.1

Multiply $6$ by $1$ .

$7 x - y + 6 + 6 (- 9 x) + 6 (- 8 y) = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 2.4.1.1.2.2

Multiply $- 9$ by $6$ .

$7 x - y + 6 - 54 x + 6 (- 8 y) = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 2.4.1.1.2.3

Multiply $- 8$ by $6$ .

$7 x - y + 6 - 54 x - 48 y = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 - 54 x - 48 y = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$7 x - y + 6 - 54 x - 48 y = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 2.4.1.2

Simplify by adding terms.

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Step 2.4.1.2.1

Subtract $54 x$ from $7 x$ .

$- 47 x - y + 6 - 48 y = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 2.4.1.2.2

Subtract $48 y$ from $- y$ .

$- 47 x - 49 y + 6 = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$- 47 x - 49 y + 6 = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$- 47 x - 49 y + 6 = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$- 47 x - 49 y + 6 = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$- 47 x - 49 y + 6 = 1$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 3

Solve for $x$ in $- 47 x - 49 y + 6 = 1$ .

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Step 3.1

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

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Step 3.1.1

Add $49 y$ to both sides of the equation.

$- 47 x + 6 = 1 + 49 y$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 3.1.2

Subtract $6$ from both sides of the equation.

$- 47 x = 1 + 49 y - 6$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 3.1.3

Subtract $6$ from $1$ .

$- 47 x = 49 y - 5$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$- 47 x = 49 y - 5$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 3.2

Divide each term in $- 47 x = 49 y - 5$ by $- 47$ and simplify.

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Step 3.2.1

Divide each term in $- 47 x = 49 y - 5$ by $- 47$ .

$\frac{- 47 x}{- 47} = \frac{49 y}{- 47} + \frac{- 5}{- 47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 3.2.2

Simplify the left side.

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Step 3.2.2.1

Cancel the common factor of $- 47$ .

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Step 3.2.2.1.1

Cancel the common factor.

$\frac{- 47 x}{- 47} = \frac{49 y}{- 47} + \frac{- 5}{- 47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 3.2.2.1.2

Divide $x$ by $1$ .

$x = \frac{49 y}{- 47} + \frac{- 5}{- 47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$x = \frac{49 y}{- 47} + \frac{- 5}{- 47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$x = \frac{49 y}{- 47} + \frac{- 5}{- 47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 3.2.3

Simplify the right side.

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Step 3.2.3.1

Simplify each term.

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Step 3.2.3.1.1

Move the negative in front of the fraction.

$x = - \frac{49 y}{47} + \frac{- 5}{- 47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 3.2.3.1.2

Dividing two negative values results in a positive value.

$x = - \frac{49 y}{47} + \frac{5}{47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$47 x + 49 y - 5 = 0$

$z = 1 - 9 x - 8 y$

Step 4

Replace all occurrences of $x$ with $- \frac{49 y}{47} + \frac{5}{47}$ in each equation.

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Step 4.1

Replace all occurrences of $x$ in $47 x + 49 y - 5 = 0$ with $- \frac{49 y}{47} + \frac{5}{47}$ .

$47 (- \frac{49 y}{47} + \frac{5}{47}) + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.2

Simplify the left side.

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Step 4.2.1

Simplify $47 (- \frac{49 y}{47} + \frac{5}{47}) + 49 y - 5$ .

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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.

$47 (- \frac{49 y}{47}) + 47 (\frac{5}{47}) + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.2.1.1.2

Cancel the common factor of $47$ .

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Step 4.2.1.1.2.1

Move the leading negative in $- \frac{49 y}{47}$ into the numerator.

$47 (\frac{- 49 y}{47}) + 47 (\frac{5}{47}) + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.2.1.1.2.2

Cancel the common factor.

$47 (\frac{- 49 y}{47}) + 47 (\frac{5}{47}) + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.2.1.1.2.3

Rewrite the expression.

$- 49 y + 47 (\frac{5}{47}) + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

$- 49 y + 47 (\frac{5}{47}) + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.2.1.1.3

Cancel the common factor of $47$ .

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Step 4.2.1.1.3.1

Cancel the common factor.

$- 49 y + 47 (\frac{5}{47}) + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.2.1.1.3.2

Rewrite the expression.

$- 49 y + 5 + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

$- 49 y + 5 + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

$- 49 y + 5 + 49 y - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.2.1.2

Combine the opposite terms in $- 49 y + 5 + 49 y - 5$ .

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Step 4.2.1.2.1

Add $- 49 y$ and $49 y$ .

$0 + 5 - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.2.1.2.2

Add $0$ and $5$ .

$5 - 5 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.2.1.2.3

Subtract $5$ from $5$ .

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 - 9 x - 8 y$

Step 4.3

Replace all occurrences of $x$ in $z = 1 - 9 x - 8 y$ with $- \frac{49 y}{47} + \frac{5}{47}$ .

$z = 1 - 9 (- \frac{49 y}{47} + \frac{5}{47}) - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4

Simplify the right side.

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Step 4.4.1

Simplify $1 - 9 (- \frac{49 y}{47} + \frac{5}{47}) - 8 y$ .

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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.

$z = 1 - 9 (- \frac{49 y}{47}) - 9 (\frac{5}{47}) - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.1.2

Multiply $- 9 (- \frac{49 y}{47})$ .

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Step 4.4.1.1.2.1

Multiply $- 1$ by $- 9$ .

$z = 1 + 9 (\frac{49 y}{47}) - 9 (\frac{5}{47}) - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.1.2.2

Combine $9$ and $\frac{49 y}{47}$ .

$z = 1 + \frac{9 (49 y)}{47} - 9 (\frac{5}{47}) - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.1.2.3

Multiply $49$ by $9$ .

$z = 1 + \frac{441 y}{47} - 9 (\frac{5}{47}) - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 + \frac{441 y}{47} - 9 (\frac{5}{47}) - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.1.3

Multiply $- 9 (\frac{5}{47})$ .

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Step 4.4.1.1.3.1

Combine $- 9$ and $\frac{5}{47}$ .

$z = 1 + \frac{441 y}{47} + \frac{- 9 \cdot 5}{47} - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.1.3.2

Multiply $- 9$ by $5$ .

$z = 1 + \frac{441 y}{47} + \frac{- 45}{47} - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 + \frac{441 y}{47} + \frac{- 45}{47} - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.1.4

Move the negative in front of the fraction.

$z = 1 + \frac{441 y}{47} - \frac{45}{47} - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = 1 + \frac{441 y}{47} - \frac{45}{47} - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.2

Simplify the expression.

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Step 4.4.1.2.1

Write $1$ as a fraction with a common denominator.

$z = \frac{441 y}{47} + \frac{47}{47} - \frac{45}{47} - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.2.2

Combine the numerators over the common denominator.

$z = \frac{441 y}{47} + \frac{47 - 45}{47} - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.2.3

Subtract $45$ from $47$ .

$z = \frac{441 y}{47} + \frac{2}{47} - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = \frac{441 y}{47} + \frac{2}{47} - 8 y$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.3

To write $- 8 y$ as a fraction with a common denominator, multiply by $\frac{47}{47}$ .

$z = \frac{441 y}{47} - 8 y \cdot \frac{47}{47} + \frac{2}{47}$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.4

Combine $- 8 y$ and $\frac{47}{47}$ .

$z = \frac{441 y}{47} + \frac{- 8 y \cdot 47}{47} + \frac{2}{47}$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.5

Combine the numerators over the common denominator.

$z = \frac{441 y - 8 y \cdot 47}{47} + \frac{2}{47}$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.6

Combine the numerators over the common denominator.

$z = \frac{441 y - 8 y \cdot 47 + 2}{47}$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.7

Multiply $47$ by $- 8$ .

$z = \frac{441 y - 376 y + 2}{47}$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 4.4.1.8

Subtract $376 y$ from $441 y$ .

$z = \frac{65 y + 2}{47}$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = \frac{65 y + 2}{47}$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = \frac{65 y + 2}{47}$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

$z = \frac{65 y + 2}{47}$

$0 = 0$

$x = - \frac{49 y}{47} + \frac{5}{47}$

Step 5

Remove any equations from the system that are always true.

$z = \frac{65 y + 2}{47}$

$x = - \frac{49 y}{47} + \frac{5}{47}$