Use the matrix tool to find the solution to the system of equations. Enter the z-value of the solution in the box below.
Understand the Problem
The question requires solving a system of equations using a matrix tool and finding the z-value of the solution. It presents the system of equations and asks for the correct z value to be inputted in a numerical format.
Answer
$1$
Answer for screen readers
The value of $z$ is $1$.
Steps to Solve
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Write the equations in matrix form
We can express the system of equations in augmented matrix form: $$ \begin{bmatrix} 3 & -1 & -1 & | & 3 \ -2 & 3 & 1 & | & -3 \ 4 & -2 & -2 & | & 2 \end{bmatrix} $$ -
Use Gaussian elimination
We perform row operations to get the matrix in row-echelon form.- Start with the first row: $R_1: \begin{bmatrix} 3 & -1 & -1 | 3 \end{bmatrix}$.
- Make the first element of the second row a zero by row operation: (R_2 = R_2 + \frac{2}{3}R_1): $R_2: \begin{bmatrix} 0 & \frac{7}{3} & -\frac{1}{3} | 1 \end{bmatrix}$.
- Next, eliminate below the $R_1$: (R_3 = R_3 - \frac{4}{3}R_1): $R_3: \begin{bmatrix} 0 & -\frac{2}{3} & -\frac{2}{3} | -2 \end{bmatrix}$.
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Continuing Gaussian elimination
Next, simplify (R_3) using (R_2):- Multiply (R_2) by $3$ to eliminate fractions:
$R_2: \begin{bmatrix} 0 & 7 & -1 | 3 \end{bmatrix}$. - Scale: (R_3 + \frac{2}{7}R_2):
$R_3: \begin{bmatrix} 0 & 0 & -1 | -1 \end{bmatrix}$.
- Multiply (R_2) by $3$ to eliminate fractions:
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Back substitution
Convert this matrix back into system of equations: $$ z = 1 $$ From (R_2): $y = \frac{3 + z}{7} = \frac{3 + 1}{7} = \frac{4}{7}$ From (R_1): $3x - y - 1 = 3 \rightarrow x = 2$. -
Identify the z-value
The solution to the system requires the value of $z$ which is 1.
The value of $z$ is $1$.
More Information
This solution demonstrates how to solve a system of linear equations using matrix methods, specifically Gaussian elimination. It's a structured method that can be applied to more complex systems as well.
Tips
- Skipping the row operations or forgetting to simplify the matrix properly can lead to incorrect results. Always ensure each step follows logically and check your arithmetic.
- Incorrectly interpreting the final row echelon form can lead to mistakes in back substitution.
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