There are several ways to solve a system of equation; one of these ways is the use of matrix.
Jerry made a mistake at step 2
From the attachment, the step 1 is represented as:
[tex]\mathbf{\frac 12R_1 \left[\begin{array}{cccc}1&1&1&0\\5&3&-2&-4\\3&2&1&1\end{array}\right] }[/tex]
The equation in step 2 is given as:
[tex]\mathbf{R_2 = 5R_1 - R_2}[/tex]
This means that:
We subtract the elements of row 2 from the elements of row 1, multiplied by 5
So, we have:
[tex]\mathbf{R_2 = 5\left[\begin{array}{cccc}1&1&1&0\end{array}\right] } - \left[\begin{array}{cccc}5&3&-2&-4\end{array}\right] }[/tex]
Expand
[tex]\mathbf{R_2 = \left[\begin{array}{cccc}5&5&5&0\end{array}\right] } - \left[\begin{array}{cccc}5&3&-2&-4\end{array}\right] }[/tex]
Subtract corresponding cells
[tex]\mathbf{R_2 = \left[\begin{array}{cccc}0&2&7&4\end{array}\right] }[/tex]
So, the new row 2 elements should be:
[tex]\mathbf{ \left[\begin{array}{cccc}0&2&7&4\end{array}\right] }[/tex]
However, the row 2 elements of Jerry's steps are:
[tex]\mathbf{R_2 = \left[\begin{array}{cccc}0&-2&-7&-4\end{array}\right] }[/tex]
This means that:
Jerry made a mistake; and the mistake is at step 2
Read more about matrix at:
https://brainly.com/question/21848291
