Westonci.ca is your trusted source for accurate answers to all your questions. Join our community and start learning today! Get immediate answers to your questions from a wide network of experienced professionals on our Q&A platform. Experience the ease of finding precise answers to your questions from a knowledgeable community of experts.

Use matrices to solve the system of linear equations, if possible. Use Gauss-Jordan elimination. (If there is no solution, enter NO SOLUTION. If there are infinitely many solutions, express [tex]$x, y$[/tex], and [tex]$z$[/tex] in terms of the real number [tex]$a$[/tex].)

[tex]\[
\begin{cases}
2x - y + 3z = 12 \\
2y - z = 14 \\
7x - 5y = 9
\end{cases}
\][/tex]

[tex]\[
(x, y, z) = \left( \boxed{\phantom{0}}, \boxed{\phantom{0}}, \boxed{\phantom{0}} \right)
\][/tex]

Sagot :

To solve the given system of linear equations using Gauss-Jordan elimination, we will follow a step-by-step approach:

1. Write the augmented matrix for the system of equations:

The system of linear equations is:
[tex]\[ \begin{aligned} 2x - y + 3z &= 12 \quad \text{(Equation 1)} \\ 0x + 2y - z &= 14 \quad \text{(Equation 2)} \\ 7x - 5y + 0z &= 9 \quad \text{(Equation 3)} \end{aligned} \][/tex]

The augmented matrix is:
[tex]\[ \left[ \begin{array}{ccc|c} 2 & -1 & 3 & 12 \\ 0 & 2 & -1 & 14 \\ 7 & -5 & 0 & 9 \\ \end{array} \right] \][/tex]

2. Apply Gauss-Jordan elimination to the augmented matrix:

Step 1: Make the element in the first row, first column a 1 (pivot).
Divide the whole first row by 2:
[tex]\[ \left[ \begin{array}{ccc|c} 1 & -\frac{1}{2} & \frac{3}{2} & 6 \\ 0 & 2 & -1 & 14 \\ 7 & -5 & 0 & 9 \\ \end{array} \right] \][/tex]

Step 2: Eliminate the first column elements for the second and third rows.
- For the third row, [tex]\( R_3 - 7R_1 \)[/tex]:
[tex]\[ R_3 = \left[ \begin{array}{ccc|c} 7 & -5 & 0 & 9 \end{array} \right] - 7\left[ \begin{array}{ccc|c} 1 & -\frac{1}{2} & \frac{3}{2} & 6 \end{array} \right] = \left[ \begin{array}{ccc|c} 0 & -\frac{1}{2} & -\frac{21}{2} & -33 \end{array} \right] \][/tex]

Our matrix becomes:
[tex]\[ \left[ \begin{array}{ccc|c} 1 & -\frac{1}{2} & \frac{3}{2} & 6 \\ 0 & 2 & -1 & 14 \\ 0 & -\frac{1}{2} & -\frac{21}{2} & -33 \\ \end{array} \right] \][/tex]

Step 3: Eliminate the first column element for the third row by scaling the rows.
Multiply the second row by [tex]\( \frac{1}{2} \)[/tex] and add to the third row:
[tex]\[ R_3 = \left[ \begin{array}{ccc|c} 0 & 2 & -1 & 14 \end{array} \right] \frac{1}{2} + \left[ \begin{array}{ccc|c} 0 & -\frac{1}{2} & -\frac{21}{2} & -33 \end{array} \right] = \left[ \begin{array}{ccc|c} 0 & 0 & -11 & -26 \end{array} \right] \][/tex]

Now, the matrix becomes:
[tex]\[ \left[ \begin{array}{ccc|c} 1 & -\frac{1}{2} & \frac{3}{2} & 6 \\ 0 & 2 & -1 & 14 \\ 0 & 0 & -11 & -26 \\ \end{array} \right] \][/tex]

Step 4: Make the element in the second row, second column a 1.
Divide the whole second row by 2:
[tex]\[ \left[ \begin{array}{ccc|c} 1 & -\frac{1}{2} & \frac{3}{2} & 6 \\ 0 & 1 & -\frac{1}{2} & 7 \\ 0 & 0 & -11 & -26 \\ \end{array} \left[ \begin{array}{ccc|c} 1 & -\frac{1}{2} & \frac{3}{2} & 6 \\ 0 & 1 & -\frac{1}{2} & 7 \\ 0 & 0 & 1 & \frac{26}{11} \\ \end{array} \right] } \][/tex]

Step 5: Eliminate the second column element for the first row.
- For the first row, [tex]\( R_1 + \frac{1}{2} R_2 \)[/tex]:
[tex]\[ R_1 = \left[ \begin{array}{ccc|c} 1 & -\frac{1}{2} & \frac{3}{2} & 6 \end{array} \right] + \frac{1}{2}\left[ \begin{array}{ccc|c} 0 & 1 & -\frac{1}{2} & 7 \end{array} \right] = \left[ \begin{array}{ccc|c} 1 & 0 & 1 & 9.5 \end{array} \right] \][/tex]

Our matrix becomes:
[tex]\[ \left[ \begin{array}{ccc|c} 1 & 0 & 1 & 9.5 \quad \text{(divide row first, eliminate second and third row columns too)} \\ 0 & 1 & -\frac{1}{2} & 7 \\ 0 & 0 & 1 & \frac{26}{11} \\ \end{array} \right] \][/tex]

Step 6: Make back substitution and checking final reduced rows.
\[
\begin{eqnarray}
\begin{cases}
x = 9.5\\
y = 7 \\
z = \frac{26}{11}
\end{cases}
\end{eqnarray}
}
So the final values for variables would be x = 9.5, y = 7.
Thanks for using our service. We're always here to provide accurate and up-to-date answers to all your queries. Thank you for choosing our platform. We're dedicated to providing the best answers for all your questions. Visit us again. Get the answers you need at Westonci.ca. Stay informed with our latest expert advice.