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Use Gauss-Jordan elimination to solve the following linear system:

[tex]\[
\begin{array}{l}
-3x + 4y = -6 \\
5x - y = 10
\end{array}
\][/tex]

A. [tex]\((2,0)\)[/tex]

B. [tex]\((2,2)\)[/tex]

C. [tex]\((-6,2)\)[/tex]

D. [tex]\((2,-5)\)[/tex]


Sagot :

To solve the given linear system using Gauss-Jordan elimination, follow these detailed steps:

1. Write the system of equations in augmented matrix form:
[tex]\[ \begin{pmatrix} -3 & 4 & | & -6 \\ 5 & -1 & | & 10 \end{pmatrix} \][/tex]

2. Normalize the first row to make the leading coefficient (first element) 1.
Divide each element in the first row by -3:
[tex]\[ \begin{pmatrix} 1 & -\frac{4}{3} & | & 2 \\ 5 & -1 & | & 10 \end{pmatrix} \][/tex]

3. Eliminate the x-term from the second row.
Use row operations to make the element in the second row, first column (5) zero. Subtract 5 times the first row from the second row:
[tex]\[ \begin{pmatrix} 1 & -\frac{4}{3} & | & 2 \\ 0 & \frac{5}{3} & | & 0 \end{pmatrix} \][/tex]

4. Normalize the second row to make the leading coefficient (second element) 1.
Divide each element in the second row by [tex]\(\frac{5}{3}\)[/tex]:
[tex]\[ \begin{pmatrix} 1 & -\frac{4}{3} & | & 2 \\ 0 & 1 & | & 0 \end{pmatrix} \][/tex]

5. Eliminate the y-term from the first row.
Use row operations to make the element in the first row, second column [tex]\(-\frac{4}{3}\)[/tex] zero. Add [tex]\(\frac{4}{3}\)[/tex] times the second row to the first row:
[tex]\[ \begin{pmatrix} 1 & 0 & | & 2 \\ 0 & 1 & | & 0 \end{pmatrix} \][/tex]

Now the augmented matrix is in reduced row-echelon form (RREF). From this matrix, we can directly read off the solutions:
[tex]\[ \begin{cases} x = 2 \\ y = 0 \end{cases} \][/tex]

So the solution to the system of equations is [tex]\((2, 0)\)[/tex].

Therefore, the best answer is:
A. (2,0)