Suppose That You Are Solving a System of Three Linear $$\left[ \begin{array} { r r r r } 1 & 1 & 2 & 28 \\0 & - 9 & 12 & - 13 \\0 & 13 & - 6 & 11\end{array} \right]$$

Multiple Choice

Suppose that you are solving a system of three linear equations and three variables by the row echelon method a obtain the following augmented matrix.
$$\left[ \begin{array} { r r r r } 1 & 1 & 2 & 28 \\0 & - 9 & 12 & - 13 \\0 & 13 & - 6 & 11\end{array} \right]$$
What row transformation would you perform next?

A) Add -13 times row 1 to 1 times row 3 to obtain a zero in the third row, second column position.
B) Add row 1 to row 2 .
C) Multiply row 1 by 1 .
D) Multiply row 2 by $- \frac { 1 } { - }$ . nd you 9