Write a system of linear equations represented by the augmented matrix:

[tex]\[
\left[\begin{array}{rrr|r}
4 & 9 & -4 & -12 \\
9 & 2 & 7 & 6 \\
4 & -2 & 2 & -1
\end{array}\right]
\][/tex]

Select one:

a.
[tex]\[
4x = -12 \\
2y = 6 \\
2z = -1
\][/tex]

b.
[tex]\[
4x + 9y + 4z = -12 \\
9x + 2y - 2z = 6 \\
-4x + 7y + 2z = -1
\][/tex]

c.
[tex]\[
4x + 9y - 4z = -12 \\
9x + 2y + 7z = 6 \\
4x - 2y + 2z = -1
\][/tex]

d.
[tex]\[
4x + 9y - 4z = 12 \\
9x + 2y + 7z = -6 \\
4x - 2y + 2z = 1
\][/tex]



Answer :

To determine the system of linear equations represented by the given augmented matrix:

[tex]\[ \left[\begin{array}{rrr|r} 4 & 9 & -4 & -12 \\ 9 & 2 & 7 & 6 \\ 4 & -2 & 2 & -1 \end{array}\right] \][/tex]

we need to convert each row of the matrix into its corresponding linear equation. Each row consists of the coefficients of the variables [tex]\(x\)[/tex], [tex]\(y\)[/tex], and [tex]\(z\)[/tex], followed by the constant term after the vertical bar.

1. The first row, [tex]\([4, 9, -4, -12]\)[/tex], corresponds to the equation:
[tex]\[ 4x + 9y - 4z = -12 \][/tex]

2. The second row, [tex]\([9, 2, 7, 6]\)[/tex], corresponds to the equation:
[tex]\[ 9x + 2y + 7z = 6 \][/tex]

3. The third row, [tex]\([4, -2, 2, -1]\)[/tex], corresponds to the equation:
[tex]\[ 4x - 2y + 2z = -1 \][/tex]

Now, compiling these equations, we have the system of linear equations:
[tex]\[ \begin{cases} 4x + 9y - 4z = -12 \\ 9x + 2y + 7z = 6 \\ 4x - 2y + 2z = -1 \end{cases} \][/tex]

Comparing this with the provided options:

- Option a:
[tex]\[ \begin{cases} 4x = -12 \\ 2y = 6 \\ 2z = -1 \end{cases} \][/tex]
This does not match our system.

- Option b:
[tex]\[ \begin{cases} 4x + 9y + 4z = -12 \\ 9x + 2y - 2z = 6 \\ -4x + 7y + 2z = -1 \end{cases} \][/tex]
This does not match our system either.

- Option c:
[tex]\[ \begin{cases} 4x + 9y - 4z = -12 \\ 9x + 2y + 7z = 6 \\ 4x - 2y + 2z = -1 \end{cases} \][/tex]
This matches our system of equations exactly.

- Option d:
[tex]\[ \begin{cases} 4x + 9y - 4z = 12 \\ 9x + 2y + 7z = -6 \\ 4x - 2y + 2z = 1 \end{cases} \][/tex]
This does not match our system.

Therefore, the correct option is:
c. [tex]\(4x + 9y - 4z = -12\)[/tex], [tex]\(9x + 2y + 7z = 6\)[/tex], [tex]\(4x - 2y + 2z = -1\)[/tex].

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