Precalculus Examples

$[\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}] = 3 X + 5 [\begin{array}{c} 9 & - 9 & 6 \\ 6 & - 3 & - 3 \end{array}]$

Step 1

Simplify each term.

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Step 1.1

Multiply $5$ by each element of the matrix.

$[\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}] = 3 X + [\begin{array}{c} 5 \cdot 9 & 5 \cdot - 9 & 5 \cdot 6 \\ 5 \cdot 6 & 5 \cdot - 3 & 5 \cdot - 3 \end{array}]$

Step 1.2

Simplify each element in the matrix.

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Step 1.2.1

Multiply $5$ by $9$ .

$[\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}] = 3 X + [\begin{array}{c} 45 & 5 \cdot - 9 & 5 \cdot 6 \\ 5 \cdot 6 & 5 \cdot - 3 & 5 \cdot - 3 \end{array}]$

Step 1.2.2

Multiply $5$ by $- 9$ .

$[\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}] = 3 X + [\begin{array}{c} 45 & - 45 & 5 \cdot 6 \\ 5 \cdot 6 & 5 \cdot - 3 & 5 \cdot - 3 \end{array}]$

Step 1.2.3

Multiply $5$ by $6$ .

$[\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}] = 3 X + [\begin{array}{c} 45 & - 45 & 30 \\ 5 \cdot 6 & 5 \cdot - 3 & 5 \cdot - 3 \end{array}]$

Step 1.2.4

Multiply $5$ by $6$ .

$[\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}] = 3 X + [\begin{array}{c} 45 & - 45 & 30 \\ 30 & 5 \cdot - 3 & 5 \cdot - 3 \end{array}]$

Step 1.2.5

Multiply $5$ by $- 3$ .

$[\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}] = 3 X + [\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & 5 \cdot - 3 \end{array}]$

Step 1.2.6

Multiply $5$ by $- 3$ .

$[\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}] = 3 X + [\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}]$

Step 2

Move all terms not containing a variable to the right side.

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Step 2.1

Subtract $[\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}]$ from both sides of the equation.

$0 = 3 X + [\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}] - [\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}]$

Step 3

Move all terms containing a variable to the left side.

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Step 3.1

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

$- 3 X = [\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}] - [\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}]$

Step 4

Multiply both sides by $- \frac{1}{3}$ .

$- \frac{1}{3} (- 3 X) = - \frac{1}{3} ([\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}] - [\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}])$

Step 5

Simplify.

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Step 5.1

Cancel the common factor of $3$ .

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Step 5.1.1

Move the leading negative in $- \frac{1}{3}$ into the numerator.

$\frac{- 1}{3} (- 3 X) = - \frac{1}{3} ([\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}] - [\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}])$

Step 5.1.2

Factor $3$ out of $- 3 X$ .

$\frac{- 1}{3} (3 (- X)) = - \frac{1}{3} ([\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}] - [\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}])$

Step 5.1.3

Cancel the common factor.

$\frac{- 1}{3} (3 (- X)) = - \frac{1}{3} ([\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}] - [\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}])$

Step 5.1.4

Rewrite the expression.

$- - X = - \frac{1}{3} ([\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}] - [\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}])$

Step 5.2

Multiply $- 1$ by $- 1$ .

$1 X = - \frac{1}{3} ([\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}] - [\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}])$

Step 5.3

Multiply $X$ by $1$ .

$X = - \frac{1}{3} ([\begin{array}{c} 45 & - 45 & 30 \\ 30 & - 15 & - 15 \end{array}] - [\begin{array}{c} - 9 & - 2 & - 2 \\ - 6 & 2 & - 7 \end{array}])$

Step 5.4

Subtract the corresponding elements.

$X = - \frac{1}{3} [\begin{array}{c} 45 + 9 & - 45 + 2 & 30 + 2 \\ 30 + 6 & - 15 - 2 & - 15 + 7 \end{array}]$

Step 5.5

Simplify each element.

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Step 5.5.1

Add $45$ and $9$ .

$X = - \frac{1}{3} [\begin{array}{c} 54 & - 45 + 2 & 30 + 2 \\ 30 + 6 & - 15 - 2 & - 15 + 7 \end{array}]$

Step 5.5.2

Add $- 45$ and $2$ .

$X = - \frac{1}{3} [\begin{array}{c} 54 & - 43 & 30 + 2 \\ 30 + 6 & - 15 - 2 & - 15 + 7 \end{array}]$

Step 5.5.3

Add $30$ and $2$ .

$X = - \frac{1}{3} [\begin{array}{c} 54 & - 43 & 32 \\ 30 + 6 & - 15 - 2 & - 15 + 7 \end{array}]$

Step 5.5.4

Add $30$ and $6$ .

$X = - \frac{1}{3} [\begin{array}{c} 54 & - 43 & 32 \\ 36 & - 15 - 2 & - 15 + 7 \end{array}]$

Step 5.5.5

Subtract $2$ from $- 15$ .

$X = - \frac{1}{3} [\begin{array}{c} 54 & - 43 & 32 \\ 36 & - 17 & - 15 + 7 \end{array}]$

Step 5.5.6

Add $- 15$ and $7$ .

$X = - \frac{1}{3} [\begin{array}{c} 54 & - 43 & 32 \\ 36 & - 17 & - 8 \end{array}]$

Step 5.6

Multiply $- \frac{1}{3}$ by each element of the matrix.

$X = [\begin{array}{c} - \frac{1}{3} \cdot 54 & - \frac{1}{3} \cdot - 43 & - \frac{1}{3} \cdot 32 \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7

Simplify each element in the matrix.

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Step 5.7.1

Cancel the common factor of $3$ .

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Step 5.7.1.1

Move the leading negative in $- \frac{1}{3}$ into the numerator.

$X = [\begin{array}{c} \frac{- 1}{3} \cdot 54 & - \frac{1}{3} \cdot - 43 & - \frac{1}{3} \cdot 32 \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.1.2

Factor $3$ out of $54$ .

$X = [\begin{array}{c} \frac{- 1}{3} \cdot (3 (18)) & - \frac{1}{3} \cdot - 43 & - \frac{1}{3} \cdot 32 \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.1.3

Cancel the common factor.

$X = [\begin{array}{c} \frac{- 1}{3} \cdot (3 \cdot 18) & - \frac{1}{3} \cdot - 43 & - \frac{1}{3} \cdot 32 \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.1.4

Rewrite the expression.

$X = [\begin{array}{c} - 1 \cdot 18 & - \frac{1}{3} \cdot - 43 & - \frac{1}{3} \cdot 32 \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.2

Multiply $- 1$ by $18$ .

$X = [\begin{array}{c} - 18 & - \frac{1}{3} \cdot - 43 & - \frac{1}{3} \cdot 32 \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.3

Multiply $- \frac{1}{3} \cdot - 43$ .

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Step 5.7.3.1

Multiply $- 43$ by $- 1$ .

$X = [\begin{array}{c} - 18 & 43 (\frac{1}{3}) & - \frac{1}{3} \cdot 32 \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.3.2

Combine $43$ and $\frac{1}{3}$ .

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{1}{3} \cdot 32 \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.4

Multiply $- \frac{1}{3} \cdot 32$ .

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Step 5.7.4.1

Multiply $32$ by $- 1$ .

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - 32 (\frac{1}{3}) \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.4.2

Combine $- 32$ and $\frac{1}{3}$ .

$X = [\begin{array}{c} - 18 & \frac{43}{3} & \frac{- 32}{3} \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.5

Move the negative in front of the fraction.

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ - \frac{1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.6

Cancel the common factor of $3$ .

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Step 5.7.6.1

Move the leading negative in $- \frac{1}{3}$ into the numerator.

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ \frac{- 1}{3} \cdot 36 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.6.2

Factor $3$ out of $36$ .

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ \frac{- 1}{3} \cdot (3 (12)) & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.6.3

Cancel the common factor.

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ \frac{- 1}{3} \cdot (3 \cdot 12) & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.6.4

Rewrite the expression.

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ - 1 \cdot 12 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.7

Multiply $- 1$ by $12$ .

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ - 12 & - \frac{1}{3} \cdot - 17 & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.8

Multiply $- \frac{1}{3} \cdot - 17$ .

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Step 5.7.8.1

Multiply $- 17$ by $- 1$ .

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ - 12 & 17 (\frac{1}{3}) & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.8.2

Combine $17$ and $\frac{1}{3}$ .

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ - 12 & \frac{17}{3} & - \frac{1}{3} \cdot - 8 \end{array}]$

Step 5.7.9

Multiply $- \frac{1}{3} \cdot - 8$ .

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Step 5.7.9.1

Multiply $- 8$ by $- 1$ .

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ - 12 & \frac{17}{3} & 8 (\frac{1}{3}) \end{array}]$

Step 5.7.9.2

Combine $8$ and $\frac{1}{3}$ .

$X = [\begin{array}{c} - 18 & \frac{43}{3} & - \frac{32}{3} \\ - 12 & \frac{17}{3} & \frac{8}{3} \end{array}]$