Algebra Examples

$[\begin{array}{c} - 3 & - 4 \\ 1 & 0 \end{array}] x + [\begin{array}{c} - 7 & - 9 \\ 4 & - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$

Step 1

Reorder factors in $[\begin{array}{c} - 3 & - 4 \\ 1 & 0 \end{array}] x + [\begin{array}{c} - 7 & - 9 \\ 4 & - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$ .

$x [\begin{array}{c} - 3 & - 4 \\ 1 & 0 \end{array}] + [\begin{array}{c} - 7 & - 9 \\ 4 & - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$

Step 2

Simplify.

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Step 2.1

Simplify each term.

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Step 2.1.1

Multiply $x$ by each element of the matrix.

$[\begin{array}{c} x \cdot - 3 & x \cdot - 4 \\ x \cdot 1 & x \cdot 0 \end{array}] + [\begin{array}{c} - 7 & - 9 \\ 4 & - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$

Step 2.1.2

Simplify each element in the matrix.

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Step 2.1.2.1

Move $- 3$ to the left of $x$ .

$[\begin{array}{c} - 3 x & x \cdot - 4 \\ x \cdot 1 & x \cdot 0 \end{array}] + [\begin{array}{c} - 7 & - 9 \\ 4 & - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$

Step 2.1.2.2

Move $- 4$ to the left of $x$ .

$[\begin{array}{c} - 3 x & - 4 x \\ x \cdot 1 & x \cdot 0 \end{array}] + [\begin{array}{c} - 7 & - 9 \\ 4 & - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$

Step 2.1.2.3

Multiply $x$ by $1$ .

$[\begin{array}{c} - 3 x & - 4 x \\ x & x \cdot 0 \end{array}] + [\begin{array}{c} - 7 & - 9 \\ 4 & - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$

Step 2.1.2.4

Multiply $x$ by $0$ .

$[\begin{array}{c} - 3 x & - 4 x \\ x & 0 \end{array}] + [\begin{array}{c} - 7 & - 9 \\ 4 & - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$

Step 2.2

Add the corresponding elements.

$[\begin{array}{c} - 3 x - 7 & - 4 x - 9 \\ x + 4 & 0 - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$

Step 2.3

Subtract $1$ from $0$ .

$[\begin{array}{c} - 3 x - 7 & - 4 x - 9 \\ x + 4 & - 1 \end{array}] = [\begin{array}{c} - 42 & - 20 \\ 5 & 4 \end{array}]$

Step 3

Write as a linear system of equations.

$- 3 x - 7 = - 42$

$- 4 x - 9 = - 20$

$x + 4 = 5$

$- 1 = 4$

Step 4

Since $- 1 \neq 4$ , the matrix equation has no solution.

No solution