Perform the indicated row operation:
[tex]\[
\left[\begin{array}{ccc|c}
2 & -1 & -4 & 7 \\
-1 & 2 & 1 & -1 \\
0 & 10 & 8 & 2
\end{array}\right] \xrightarrow{2R_2 + R_1 \rightarrow R_2}
\left[\begin{array}{ccc|c}
2 & -1 & -4 & 7 \\
0 & 0 & -2 & 5 \\
0 & 10 & 8 & 2
\end{array}\right]
\][/tex]



Answer :

Certainly! Let's work through the row operation step-by-step.

We are given the initial matrix:
[tex]\[ \left[\begin{array}{ccc|c} 2 & -1 & -4 & 7 \\ -1 & 2 & 1 & -1 \\ 0 & 10 & 8 & 2 \end{array}\right] \][/tex]

We need to perform the row operation [tex]\(2R_2 + R_1 \rightarrow R_2\)[/tex], which means we will replace the second row [tex]\(R_2\)[/tex] with [tex]\(2 \times R_2 + R_1\)[/tex].

Let's break down the operation for each element of the second row:

1. First element of [tex]\(R_2\)[/tex]:
[tex]\[ 2 \times (-1) + 2 = -2 + 2 = 0 \][/tex]

2. Second element of [tex]\(R_2\)[/tex]:
[tex]\[ 2 \times 2 + (-1) = 4 - 1 = 3 \][/tex]

3. Third element of [tex]\(R_2\)[/tex]:
[tex]\[ 2 \times 1 + (-4) = 2 - 4 = -2 \][/tex]

4. Fourth element of [tex]\(R_2\)[/tex]:
[tex]\[ 2 \times (-1) + 7 = -2 + 7 = 5 \][/tex]

So, the new second row after the operation [tex]\(2R_2 + R_1\)[/tex] becomes:
[tex]\[ [0, 3, -2, 5] \][/tex]

Now, we substitute this new row back into the original matrix, leaving the first and third rows unchanged:
[tex]\[ \left[\begin{array}{ccc|c} 2 & -1 & -4 & 7 \\ 0 & 3 & -2 & 5 \\ 0 & 10 & 8 & 2 \end{array}\right] \][/tex]

Therefore, the resulting matrix after the row operation [tex]\(2R_2 + R_1 \rightarrow R_2\)[/tex] is:
[tex]\[ \left[\begin{array}{ccc|c} 2 & -1 & -4 & 7 \\ 0 & 3 & -2 & 5 \\ 0 & 10 & 8 & 2 \end{array}\right] \][/tex]