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Ch. 5 - Systems and Matrices
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
All textbooksLial 13th EditionCh. 5 - Systems and MatricesProblem 55
Chapter 6, Problem 55

Use the determinant theorems to evaluate each determinant. See Example 4.
∣2−136410457∣\(\begin{vmatrix}\)2&-1&3\\6&4 &10\\4&5&7\(\end{vmatrix}\)

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1
Identify the size and structure of the given determinant matrix to understand which determinant theorems can be applied effectively.
Recall key determinant theorems such as: the determinant of a matrix with two identical rows is zero, swapping two rows changes the sign of the determinant, and the determinant of a triangular matrix is the product of its diagonal entries.
Apply row operations that simplify the matrix to a form where the determinant is easier to calculate, keeping track of how each operation affects the determinant value according to the theorems.
Use the properties that multiplying a row by a scalar multiplies the determinant by that scalar, and adding a multiple of one row to another row does not change the determinant, to further simplify the matrix.
Once the matrix is in a simplified form (such as upper triangular), calculate the determinant by multiplying the diagonal entries, then adjust the result based on the row operations performed.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Determinant of a Matrix

The determinant is a scalar value computed from a square matrix that provides important properties such as invertibility. It can be calculated using various methods, including expansion by minors or row operations, and is essential for solving systems of linear equations and understanding matrix behavior.
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Determinant Theorems

Determinant theorems are rules that simplify the calculation of determinants, such as the effect of row swaps, scalar multiplication of rows, and adding multiples of one row to another. These theorems help reduce complex determinants to simpler forms without changing their values or by adjusting them predictably.
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Application of Determinant Theorems in Evaluation

Using determinant theorems strategically allows for efficient evaluation of determinants by transforming matrices into easier forms. This approach avoids direct expansion and leverages properties like linearity and row operations to compute determinants quickly and accurately.
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Related Practice
Textbook Question

Solve each problem using a system of equations in two variables. See Example 6. Find two numbers whose sum is 17 and whose product is 42.

Textbook Question

Solve each problem using a system of equations in two variables. See Example 6. Find two numbers whose squares have a sum of 100 and a difference of 28.

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Textbook Question

Use the determinant theorems to evaluate each determinant.

∣−102354−37829−544−110∣\(\left\)| \(\begin{matrix}\) -1 & 0 & 2 & 3 \\ 5 & 4 & -3 & 7 \\ 8 & 2 & 9 & -5 \\ 4 & 4 & -1 & 10 \(\end{matrix}\) \(\right\)|

Textbook Question

Use the determinant theorems to evaluate each determinant.

∣167067009∣\(\left\)| \(\begin{matrix}\) 1 & 6 & 7 \\ 0 & 6 & 7 \\ 0 & 0 & 9 \(\end{matrix}\) \(\right\)|

Textbook Question

Find each product, if possible.

[1234][−17]\(\left\)[ \(\begin{matrix}\) 1 & 2 \\ 3 & 4 \(\end{matrix}\) \(\right\)] \(\left\)[ \(\begin{matrix}\) -1 \\ 7 \(\end{matrix}\) \(\right\)]

Textbook Question

Find each product, if possible.

[3−41502][−142]\(\left\)[ \(\begin{matrix}\) 3 & -4 & 1 \\ 5 & 0 & 2 \(\end{matrix}\) \(\right\)] \(\left\)[ \(\begin{matrix}\) -1 \\ 4 \\ 2 \(\end{matrix}\) \(\right\)]