Precalculus Examples

$[\begin{array}{c} 1 & 0 & 0 & 31 \\ 0 & 1 & 1 & 45 \\ 0 & 0 & 1 & 87 \end{array}]$

Step 1

Perform the row operation $R_{2} = R_{2} - R_{3}$ to make the entry at $2, 3$ a $0$ .

$[\begin{array}{c} 1 & 0 & 0 & 31 \\ 0 - 0 & 1 - 0 & 1 - 1 & 45 - 87 \\ 0 & 0 & 1 & 87 \end{array}]$

Step 2

Simplify $R_{2}$ .

$[\begin{array}{c} 1 & 0 & 0 & 31 \\ 0 & 1 & 0 & - 42 \\ 0 & 0 & 1 & 87 \end{array}]$