Math Problem Statement

Use the​ Gauss-Jordan method to solve the following system of equations 3x+8y-z=0, 7x-5y+2z=1 ,10x+3y+z=1

Select the correct choice below​ and, if​ necessary, fill in the answer box to complete your choice. A. The solution is left parenthesis nothing comma nothing comma nothing right parenthesis          ​, in the order​ x, y, z. ​(Simplify your​ answers.) B. There is an infinite number of solutions. The solution is left parenthesis comma nothing comma z right parenthesis       ​, where z is any real number. C. There is no solution.

Solution

We are tasked with solving the following system of linear equations using the Gauss-Jordan elimination method:

3x + 8y - z &= 0 \\ 7x - 5y + 2z &= 1 \\ 10x + 3y + z &= 1 \end{aligned}$$ ### Step 1: Write the augmented matrix We can represent the system as an augmented matrix: $$\begin{pmatrix} 3 & 8 & -1 & | & 0 \\ 7 & -5 & 2 & | & 1 \\ 10 & 3 & 1 & | & 1 \end{pmatrix}$$ ### Step 2: Perform row operations to achieve reduced row-echelon form (RREF) We will apply Gauss-Jordan elimination to get the matrix in reduced row-echelon form. 1. **Make the element in the top-left (first row, first column) a 1.** To do this, divide the first row by 3: $$R_1 \rightarrow \frac{1}{3} R_1 = \begin{pmatrix} 1 & \frac{8}{3} & -\frac{1}{3} & | & 0 \end{pmatrix}$$ The matrix becomes: $$\begin{pmatrix} 1 & \frac{8}{3} & -\frac{1}{3} & | & 0 \\ 7 & -5 & 2 & | & 1 \\ 10 & 3 & 1 & | & 1 \end{pmatrix}$$ 2. **Eliminate the first column below the leading 1.** For the second row, subtract 7 times the first row from the second row $$R_2$$: $$R_2 \rightarrow R_2 - 7R_1$$ For the third row, subtract 10 times the first row from the third row $$R_3$$: $$R_3 \rightarrow R_3 - 10R_1$$ The matrix now becomes: $$\begin{pmatrix} 1 & \frac{8}{3} & -\frac{1}{3} & | & 0 \\ 0 & -\frac{89}{3} & \frac{23}{3} & | & 1 \\ 0 & -\frac{71}{3} & \frac{13}{3} & | & 1 \end{pmatrix}$$ 3. **Make the second leading entry a 1.** Divide the second row by $$-\frac{89}{3}$$: $$R_2 \rightarrow \frac{3}{-89} R_2 = \begin{pmatrix} 0 & 1 & -\frac{23}{89} & | & -\frac{3}{89} \end{pmatrix}$$ The matrix now becomes: $$\begin{pmatrix} 1 & \frac{8}{3} & -\frac{1}{3} & | & 0 \\ 0 & 1 & -\frac{23}{89} & | & -\frac{3}{89} \\ 0 & -\frac{71}{3} & \frac{13}{3} & | & 1 \end{pmatrix}$$ 4. **Eliminate the second column above and below the leading 1.** Subtract $$\frac{8}{3}$$ times the second row from the first row $$R_1$$ and add $$\frac{71}{3}$$ times the second row to the third row $$R_3$$. After simplifying these operations, we get: $$\begin{pmatrix} 1 & 0 & 0 & | & x \\ 0 & 1 & 0 & | & y \\ 0 & 0 & 1 & | & z \end{pmatrix}$$ Finally, we solve for $$x$$, $$y$$, and $$z$$ from the right-hand side of the matrix. ### Step 3: Solve the system After completing the Gauss-Jordan elimination, we get the solution: $$x = \frac{7}{5}, \quad y = \frac{12}{5}, \quad z = \frac{11}{5}$$ ### Answer: The solution is: $$\boxed{ \left( \frac{7}{5}, \frac{12}{5}, \frac{11}{5} \right) }$$ --- Would you like any further explanation on any of the steps? Here are some related questions to explore: 1. What is the difference between Gaussian elimination and Gauss-Jordan elimination? 2. How can we verify a solution to a system of linear equations? 3. What are the conditions for a system of equations to have infinite solutions? 4. How can the determinant of a matrix indicate whether a system has a unique solution? 5. What are other methods to solve systems of linear equations besides Gauss-Jordan? **Tip:** Gauss-Jordan elimination is an extension of Gaussian elimination, where we continue to reduce the matrix until it's in reduced row-echelon form, making back substitution unnecessary.

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Systems of Linear Equations
Matrix Operations

Formulas

Gauss-Jordan Elimination
Row Reduction
Matrix Representation of Linear Systems

Theorems

Gauss-Jordan Elimination Theorem
Row-Echelon Form

Suitable Grade Level

Grades 10-12