Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
7. Systems of Equations & Matrices
Determinants and Cramer's Rule
Problem 39c
Textbook Question
In Exercises 37 - 42,
a. Write each linear system as a matrix equation in the form AX = B.
b. Solve the system using the inverse that is given for the coefficient matrix.
x - y + z = 8
2y - z = - 7
2x + 3y = 1
The inverse of is ![Linear system of equations and its coefficient matrix inverse for college algebra exercise.](https://lightcat-files.s3.amazonaws.com/problem_images/64bfc0e12cdef85c-1678243357189.jpg)
![](/channels/images/assetPage/verifiedSolution.png)
1
Write the system of equations in matrix form: AX = B, where A is the coefficient matrix, X is the column matrix of variables, and B is the column matrix of constants.
Identify the coefficient matrix A as \( \begin{bmatrix} 1 & -1 & 1 \\ 0 & 2 & -1 \\ 2 & 3 & 0 \end{bmatrix} \), the variable matrix X as \( \begin{bmatrix} x \\ y \\ z \end{bmatrix} \), and the constant matrix B as \( \begin{bmatrix} 8 \\ -7 \\ 1 \end{bmatrix} \).
Express the matrix equation as \( \begin{bmatrix} 1 & -1 & 1 \\ 0 & 2 & -1 \\ 2 & 3 & 0 \end{bmatrix} \begin{bmatrix} x \\ y \\ z \end{bmatrix} = \begin{bmatrix} 8 \\ -7 \\ 1 \end{bmatrix} \).
Use the given inverse matrix \( \begin{bmatrix} 3 & 3 & -1 \\ -2 & -2 & 1 \\ -4 & -5 & 2 \end{bmatrix} \) to solve for X by multiplying both sides of the equation by the inverse of A.
Calculate \( X = A^{-1}B \) by performing the matrix multiplication \( \begin{bmatrix} 3 & 3 & -1 \\ -2 & -2 & 1 \\ -4 & -5 & 2 \end{bmatrix} \begin{bmatrix} 8 \\ -7 \\ 1 \end{bmatrix} \) to find the values of x, y, and z.
Recommended similar problem, with video answer:
![](/channels/images/assetPage/verifiedSolution.png)
This video solution was recommended by our tutors as helpful for the problem above
Video duration:
4mPlay a video:
Was this helpful?
Watch next
Master Determinants of 2×2 Matrices with a bite sized video explanation from Patrick Ford
Start learningRelated Videos
Related Practice