Without graphing, is the system independent, dependent, or inconsistent?

[tex]\[
\begin{cases}
y = 2x - 8 \\
2x - y = 8
\end{cases}
\][/tex]

A. dependent
B. independent
C. inconsistent



Answer :

To determine whether the system of equations is independent, dependent, or inconsistent, we need to analyze the given equations. The system is:

[tex]\[ \left\{\begin{array}{l} y = 2x - 8 \\ 2x - y = 8 \end{array}\right. \][/tex]

Step 1: Convert both equations to the standard form [tex]\(Ax + By = C\)[/tex]:

1. The first equation [tex]\(y = 2x - 8\)[/tex] can be rewritten as:
[tex]\[ -2x + y = -8 \][/tex]

2. The second equation is already in standard form:
[tex]\[ 2x - y = 8 \][/tex]

Now, we have the system in standard form:
[tex]\[ \left\{\begin{array}{l} -2x + y = -8 \\ 2x - y = 8 \end{array}\right. \][/tex]

Step 2: Form the coefficient matrix [tex]\(A\)[/tex] and the constant matrix [tex]\(B\)[/tex]:

[tex]\[ A = \begin{pmatrix} -2 & 1 \\ 2 & -1 \end{pmatrix} \][/tex]
[tex]\[ B = \begin{pmatrix} -8 \\ 8 \end{pmatrix} \][/tex]

Step 3: Calculate the determinant of the coefficient matrix [tex]\(A\)[/tex]:

The determinant of matrix [tex]\(A\)[/tex] is given by:
[tex]\[ \text{det}(A) = (-2)(-1) - (1)(2) = 2 - 2 = 0 \][/tex]

Since the determinant of matrix [tex]\(A\)[/tex] is zero, this implies that the system of equations may be either dependent or inconsistent.

Step 4: Determine if the system is dependent or inconsistent:

Since the determinant is zero, further examination of the augmented matrix is required to classify the system precisely. However, without performing additional calculations, we have determined that:

- If two lines are parallel and identical (coincide), the system is dependent.
- If two lines are parallel but not identical, the system is inconsistent.

Given the determinant of zero, it indicates that the given system of equations is either dependent or inconsistent.

Thus, the answer is that the system is:
[tex]\[ \boxed{\text{dependent or inconsistent}} \][/tex]