Precalculus Examples

$2 z - 3 y = - 7$ , $5 x + 2 y = 11$

Step 1

Solve the equation for $z$ .

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Step 1.1

Simplify each term.

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Step 1.1.1

Apply the distributive property.

$2 z - 3 (\frac{11}{2}) - 3 (- \frac{5 x}{2}) = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.1.2

Multiply $- 3 (\frac{11}{2})$ .

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Step 1.1.2.1

Combine $- 3$ and $\frac{11}{2}$ .

$2 z + \frac{- 3 \cdot 11}{2} - 3 (- \frac{5 x}{2}) = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.1.2.2

Multiply $- 3$ by $11$ .

$2 z + \frac{- 33}{2} - 3 (- \frac{5 x}{2}) = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

$2 z + \frac{- 33}{2} - 3 (- \frac{5 x}{2}) = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.1.3

Multiply $- 3 (- \frac{5 x}{2})$ .

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Step 1.1.3.1

Multiply $- 1$ by $- 3$ .

$2 z + \frac{- 33}{2} + 3 (\frac{5 x}{2}) = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.1.3.2

Combine $3$ and $\frac{5 x}{2}$ .

$2 z + \frac{- 33}{2} + \frac{3 (5 x)}{2} = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.1.3.3

Multiply $5$ by $3$ .

$2 z + \frac{- 33}{2} + \frac{15 x}{2} = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

$2 z + \frac{- 33}{2} + \frac{15 x}{2} = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.1.4

Move the negative in front of the fraction.

$2 z - \frac{33}{2} + \frac{15 x}{2} = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

$2 z - \frac{33}{2} + \frac{15 x}{2} = - 7$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.2

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

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Step 1.2.1

Add $\frac{33}{2}$ to both sides of the equation.

$2 z + \frac{15 x}{2} = - 7 + \frac{33}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.2.2

Subtract $\frac{15 x}{2}$ from both sides of the equation.

$2 z = - 7 + \frac{33}{2} - \frac{15 x}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.2.3

To write $- 7$ as a fraction with a common denominator, multiply by $\frac{2}{2}$ .

$2 z = - 7 \cdot \frac{2}{2} + \frac{33}{2} - \frac{15 x}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.2.4

Combine $- 7$ and $\frac{2}{2}$ .

$2 z = \frac{- 7 \cdot 2}{2} + \frac{33}{2} - \frac{15 x}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.2.5

Combine the numerators over the common denominator.

$2 z = \frac{- 7 \cdot 2 + 33}{2} - \frac{15 x}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.2.6

Simplify the numerator.

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Step 1.2.6.1

Multiply $- 7$ by $2$ .

$2 z = \frac{- 14 + 33}{2} - \frac{15 x}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.2.6.2

Add $- 14$ and $33$ .

$2 z = \frac{19}{2} - \frac{15 x}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$2 z = \frac{19}{2} - \frac{15 x}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$2 z = \frac{19}{2} - \frac{15 x}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.3

Divide each term in $2 z = \frac{19}{2} - \frac{15 x}{2}$ by $2$ and simplify.

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Step 1.3.1

Divide each term in $2 z = \frac{19}{2} - \frac{15 x}{2}$ by $2$ .

$\frac{2 z}{2} = \frac{\frac{19}{2}}{2} + \frac{- \frac{15 x}{2}}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.3.2

Simplify the left side.

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Step 1.3.2.1

Cancel the common factor of $2$ .

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Step 1.3.2.1.1

Cancel the common factor.

$\frac{2 z}{2} = \frac{\frac{19}{2}}{2} + \frac{- \frac{15 x}{2}}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.3.2.1.2

Divide $z$ by $1$ .

$z = \frac{\frac{19}{2}}{2} + \frac{- \frac{15 x}{2}}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$z = \frac{\frac{19}{2}}{2} + \frac{- \frac{15 x}{2}}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$z = \frac{\frac{19}{2}}{2} + \frac{- \frac{15 x}{2}}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.3.3

Simplify the right side.

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Step 1.3.3.1

Simplify each term.

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Step 1.3.3.1.1

Multiply the numerator by the reciprocal of the denominator.

$z = \frac{19}{2} \cdot \frac{1}{2} + \frac{- \frac{15 x}{2}}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.3.3.1.2

Multiply $\frac{19}{2} \cdot \frac{1}{2}$ .

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Step 1.3.3.1.2.1

Multiply $\frac{19}{2}$ by $\frac{1}{2}$ .

$z = \frac{19}{2 \cdot 2} + \frac{- \frac{15 x}{2}}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.3.3.1.2.2

Multiply $2$ by $2$ .

$z = \frac{19}{4} + \frac{- \frac{15 x}{2}}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$z = \frac{19}{4} + \frac{- \frac{15 x}{2}}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.3.3.1.3

Multiply the numerator by the reciprocal of the denominator.

$z = \frac{19}{4} - \frac{15 x}{2} \cdot \frac{1}{2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.3.3.1.4

Multiply $- \frac{15 x}{2} \cdot \frac{1}{2}$ .

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Step 1.3.3.1.4.1

Multiply $\frac{1}{2}$ by $\frac{15 x}{2}$ .

$z = \frac{19}{4} - \frac{15 x}{2 \cdot 2}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 1.3.3.1.4.2

Multiply $2$ by $2$ .

$z = \frac{19}{4} - \frac{15 x}{4}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$z = \frac{19}{4} - \frac{15 x}{4}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$z = \frac{19}{4} - \frac{15 x}{4}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$z = \frac{19}{4} - \frac{15 x}{4}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$z = \frac{19}{4} - \frac{15 x}{4}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$z = \frac{19}{4} - \frac{15 x}{4}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 2

Simplify the right side.

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Step 2.1

Reorder $\frac{19}{4}$ and $- \frac{15 x}{4}$ .

$z = - \frac{15 x}{4} + \frac{19}{4}$

$y = \frac{11}{2} - \frac{5 x}{2}$

$z = - \frac{15 x}{4} + \frac{19}{4}$

$y = \frac{11}{2} - \frac{5 x}{2}$

Step 3

Simplify the right side.

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Step 3.1

Reorder $\frac{11}{2}$ and $- \frac{5 x}{2}$ .

$y = - \frac{5 x}{2} + \frac{11}{2}$

$z = - \frac{15 x}{4} + \frac{19}{4}$

$y = - \frac{5 x}{2} + \frac{11}{2}$

$z = - \frac{15 x}{4} + \frac{19}{4}$