Question

-1 -1 | -12 -3 2 | 32 How would you put this into row echelon form ?

Answer 1

$\left[\begin{array}{cc|c}-1&-1&-12\\-3&2&32\end{array}\right]$

Multiply through row 1 by -1:

$\left[\begin{array}{cc|c}1&1&12\\-3&2&32\end{array}\right]$

Add 3(row 1) to row 3:

$\left[\begin{array}{cc|c}1&1&12\\0&5&68\end{array}\right]$

Multiply through row 2 by 1/5:

$\left[\begin{array}{cc|c}1&1&12\\0&1&\frac{68}5\end{array}\right]$

Add -1(row 2) to row 1:

$\left[\begin{array}{cc|c}1&0&-\frac85\\&&\\0&1&\frac{68}5\end{array}\right]$