In Exercises 31–36, use the alternative method for evaluating third-order determinants on here to evaluate each determinant.
Ch. 6 - Matrices and Determinants

Chapter 7, Problem 33
Write each matrix equation as a system of linear equations without matrices.
Verified step by step guidance1
Identify the given matrix equation: \(\left[ \begin{array}{cc} 4 & -7 \\ 2 & -3 \end{array} \right] \left[ \begin{array}{c} x \\ y \end{array} \right] = \left[ \begin{array}{c} -3 \\ 1 \end{array} \right]\).
Recall that multiplying a matrix by a vector corresponds to forming linear combinations of the vector components with the matrix rows.
Write the first row multiplication as an equation: \$4x - 7y = -3$.
Write the second row multiplication as an equation: \$2x - 3y = 1$.
Thus, the matrix equation is equivalent to the system of linear equations: \(\begin{cases} 4x - 7y = -3 \\ 2x - 3y = 1 \end{cases}\).

Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Matrix Multiplication
Matrix multiplication involves multiplying rows of the first matrix by columns of the second matrix and summing the products. In this problem, multiplying the 2x2 coefficient matrix by the 2x1 variable matrix results in a 2x1 matrix representing the system's left side.
Recommended video:
Finding Zeros & Their Multiplicity
System of Linear Equations
A system of linear equations consists of multiple linear equations with the same variables. Writing the matrix equation as a system means expressing each row multiplication as an individual linear equation involving variables x and y.
Recommended video:
Guided course
Introduction to Systems of Linear Equations
Equating Matrices to Form Equations
When two matrices are equal, their corresponding entries are equal. This principle allows us to set each element of the product matrix equal to the corresponding element in the constant matrix, forming a system of equations to solve.
Recommended video:
Guided course
Solving Systems of Equations - Matrices (Reduced Row-Echelon Form)
Related Practice
Textbook Question
775
views
Textbook Question
Solve each system of equations using matrices. Use Gaussian elimination with back-substitution or Gauss-Jordan elimination.
1145
views
Textbook Question
Solve each system of equations using matrices. Use Gaussian elimination with back-substitution or Gauss-Jordan elimination.
926
views
Textbook Question
In Exercises 27 - 36, find (if possible) the following matrices: a. AB b. BA 1 - 1 4 1 1 0 A = 4 - 1 3 B = 1 2 4 2 0 - 2 1 - 1 3
142
views
Textbook Question
In Exercises 27 - 36, find (if possible) the following matrices: a. AB b. BA 4 2 2 3 4 A = 6 1 B = 3 5 - 1 - 2 0
920
views
Textbook Question
In Exercises 31–36, use the alternative method for evaluating third-order determinants on here to evaluate each determinant.
808
views
