Finite Math Examples

$2 x + y - 7 z = - 15$ , $4 x + 3 y + 5 z = 5$ , $x + y + 6 z = 10$

Step 1

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

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Step 1.1

Subtract $2 x$ from both sides of the equation.

$y - 7 z = - 15 - 2 x$

$4 x + 3 y + 5 z = 5$

$x + y + 6 z = 10$

Step 1.2

Add $7 z$ to both sides of the equation.

$y = - 15 - 2 x + 7 z$

$4 x + 3 y + 5 z = 5$

$x + y + 6 z = 10$

$y = - 15 - 2 x + 7 z$

$4 x + 3 y + 5 z = 5$

$x + y + 6 z = 10$

Step 2

Replace all occurrences of $y$ with $- 15 - 2 x + 7 z$ in each equation.

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Step 2.1

Replace all occurrences of $y$ in $4 x + 3 y + 5 z = 5$ with $- 15 - 2 x + 7 z$ .

$4 x + 3 (- 15 - 2 x + 7 z) + 5 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

Step 2.2

Simplify the left side.

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Step 2.2.1

Simplify $4 x + 3 (- 15 - 2 x + 7 z) + 5 z$ .

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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.

$4 x + 3 \cdot - 15 + 3 (- 2 x) + 3 (7 z) + 5 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

Step 2.2.1.1.2

Simplify.

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Step 2.2.1.1.2.1

Multiply $3$ by $- 15$ .

$4 x - 45 + 3 (- 2 x) + 3 (7 z) + 5 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

Step 2.2.1.1.2.2

Multiply $- 2$ by $3$ .

$4 x - 45 - 6 x + 3 (7 z) + 5 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

Step 2.2.1.1.2.3

Multiply $7$ by $3$ .

$4 x - 45 - 6 x + 21 z + 5 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

$4 x - 45 - 6 x + 21 z + 5 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

$4 x - 45 - 6 x + 21 z + 5 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

Step 2.2.1.2

Simplify by adding terms.

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Step 2.2.1.2.1

Subtract $6 x$ from $4 x$ .

$- 2 x - 45 + 21 z + 5 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

Step 2.2.1.2.2

Add $21 z$ and $5 z$ .

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$x + y + 6 z = 10$

Step 2.3

Replace all occurrences of $y$ in $x + y + 6 z = 10$ with $- 15 - 2 x + 7 z$ .

$x - 15 - 2 x + 7 z + 6 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 2.4

Simplify the left side.

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Step 2.4.1

Simplify $x - 15 - 2 x + 7 z + 6 z$ .

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Step 2.4.1.1

Remove parentheses.

$x - 15 - 2 x + 7 z + 6 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 2.4.1.2

Subtract $2 x$ from $x$ .

$- x - 15 + 7 z + 6 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 2.4.1.3

Add $7 z$ and $6 z$ .

$- x - 15 + 13 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$- x - 15 + 13 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$- x - 15 + 13 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$- x - 15 + 13 z = 10$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 3

Solve for $x$ in $- x - 15 + 13 z = 10$ .

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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 $15$ to both sides of the equation.

$- x + 13 z = 10 + 15$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 3.1.2

Subtract $13 z$ from both sides of the equation.

$- x = 10 + 15 - 13 z$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 3.1.3

Add $10$ and $15$ .

$- x = 25 - 13 z$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$- x = 25 - 13 z$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 3.2

Divide each term in $- x = 25 - 13 z$ by $- 1$ and simplify.

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Step 3.2.1

Divide each term in $- x = 25 - 13 z$ by $- 1$ .

$\frac{- x}{- 1} = \frac{25}{- 1} + \frac{- 13 z}{- 1}$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 3.2.2

Simplify the left side.

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Step 3.2.2.1

Dividing two negative values results in a positive value.

$\frac{x}{1} = \frac{25}{- 1} + \frac{- 13 z}{- 1}$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 3.2.2.2

Divide $x$ by $1$ .

$x = \frac{25}{- 1} + \frac{- 13 z}{- 1}$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$x = \frac{25}{- 1} + \frac{- 13 z}{- 1}$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

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

Divide $25$ by $- 1$ .

$x = - 25 + \frac{- 13 z}{- 1}$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 3.2.3.1.2

Move the negative one from the denominator of $\frac{- 13 z}{- 1}$ .

$x = - 25 - 1 \cdot (- 13 z)$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 3.2.3.1.3

Rewrite $- 1 \cdot (- 13 z)$ as $- (- 13 z)$ .

$x = - 25 - (- 13 z)$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 3.2.3.1.4

Multiply $- 13$ by $- 1$ .

$x = - 25 + 13 z$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$x = - 25 + 13 z$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$x = - 25 + 13 z$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$x = - 25 + 13 z$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

$x = - 25 + 13 z$

$- 2 x - 45 + 26 z = 5$

$y = - 15 - 2 x + 7 z$

Step 4

Replace all occurrences of $x$ with $- 25 + 13 z$ in each equation.

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Step 4.1

Replace all occurrences of $x$ in $- 2 x - 45 + 26 z = 5$ with $- 25 + 13 z$ .

$- 2 (- 25 + 13 z) - 45 + 26 z = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

Step 4.2

Simplify the left side.

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Step 4.2.1

Simplify $- 2 (- 25 + 13 z) - 45 + 26 z$ .

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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.

$- 2 \cdot - 25 - 2 (13 z) - 45 + 26 z = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

Step 4.2.1.1.2

Multiply $- 2$ by $- 25$ .

$50 - 2 (13 z) - 45 + 26 z = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

Step 4.2.1.1.3

Multiply $13$ by $- 2$ .

$50 - 26 z - 45 + 26 z = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

$50 - 26 z - 45 + 26 z = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

Step 4.2.1.2

Simplify by adding terms.

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Step 4.2.1.2.1

Combine the opposite terms in $50 - 26 z - 45 + 26 z$ .

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Step 4.2.1.2.1.1

Add $- 26 z$ and $26 z$ .

$50 + 0 - 45 = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

Step 4.2.1.2.1.2

Add $50$ and $0$ .

$50 - 45 = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

$50 - 45 = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

Step 4.2.1.2.2

Subtract $45$ from $50$ .

$5 = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

$5 = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

$5 = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

$5 = 5$

$x = - 25 + 13 z$

$y = - 15 - 2 x + 7 z$

Step 4.3

Replace all occurrences of $x$ in $y = - 15 - 2 x + 7 z$ with $- 25 + 13 z$ .

$y = - 15 - 2 (- 25 + 13 z) + 7 z$

$5 = 5$

$x = - 25 + 13 z$

Step 4.4

Simplify the right side.

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Step 4.4.1

Simplify $- 15 - 2 (- 25 + 13 z) + 7 z$ .

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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.

$y = - 15 - 2 \cdot - 25 - 2 (13 z) + 7 z$

$5 = 5$

$x = - 25 + 13 z$

Step 4.4.1.1.2

Multiply $- 2$ by $- 25$ .

$y = - 15 + 50 - 2 (13 z) + 7 z$

$5 = 5$

$x = - 25 + 13 z$

Step 4.4.1.1.3

Multiply $13$ by $- 2$ .

$y = - 15 + 50 - 26 z + 7 z$

$5 = 5$

$x = - 25 + 13 z$

$y = - 15 + 50 - 26 z + 7 z$

$5 = 5$

$x = - 25 + 13 z$

Step 4.4.1.2

Simplify by adding terms.

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Step 4.4.1.2.1

Add $- 15$ and $50$ .

$y = 35 - 26 z + 7 z$

$5 = 5$

$x = - 25 + 13 z$

Step 4.4.1.2.2

Add $- 26 z$ and $7 z$ .

$y = 35 - 19 z$

$5 = 5$

$x = - 25 + 13 z$

$y = 35 - 19 z$

$5 = 5$

$x = - 25 + 13 z$

$y = 35 - 19 z$

$5 = 5$

$x = - 25 + 13 z$

$y = 35 - 19 z$

$5 = 5$

$x = - 25 + 13 z$

$y = 35 - 19 z$

$5 = 5$

$x = - 25 + 13 z$

Step 5

Remove any equations from the system that are always true.

$y = 35 - 19 z$

$x = - 25 + 13 z$