Determine the value of [tex]\( x \)[/tex] for which the matrix

[tex]\[ \left[\begin{array}{cc} x-2 & 3 \\ 1 & 3 \end{array}\right] \][/tex]

is singular.



Answer :

To determine the value of [tex]\(x\)[/tex] that will make the matrix [tex]\(\left[\begin{array}{cc} x-2 & 3 \\ 1 & 3 \end{array}\right]\)[/tex] singular, we need to find when the determinant of the matrix is zero.

A matrix is singular if and only if its determinant is zero. We can calculate the determinant of a [tex]\(2 \times 2\)[/tex] matrix [tex]\(\left[\begin{array}{cc} a & b \\ c & d \end{array}\right]\)[/tex] using the formula:

[tex]\[ \text{det} = ad - bc \][/tex]

For the given matrix [tex]\(\left[\begin{array}{cc} x-2 & 3 \\ 1 & 3 \end{array}\right]\)[/tex]:

1. Identify the elements [tex]\(a\)[/tex], [tex]\(b\)[/tex], [tex]\(c\)[/tex], and [tex]\(d\)[/tex] in the matrix. In our case:
[tex]\[ a = x - 2, \quad b = 3, \quad c = 1, \quad d = 3 \][/tex]

2. Apply the determinant formula:
[tex]\[ \text{det} = (x - 2) \cdot 3 - 3 \cdot 1 \][/tex]

3. Simplify the expression:
[tex]\[ \text{det} = 3(x - 2) - 3 \][/tex]
[tex]\[ \text{det} = 3x - 6 - 3 \][/tex]
[tex]\[ \text{det} = 3x - 9 \][/tex]

4. Set the determinant equal to zero to find the value of [tex]\(x\)[/tex]:
[tex]\[ 3x - 9 = 0 \][/tex]

5. Solve for [tex]\(x\)[/tex]:
[tex]\[ 3x = 9 \][/tex]
[tex]\[ x = 3 \][/tex]

Therefore, the value of [tex]\(x\)[/tex] that makes the matrix singular is:

[tex]\[ x = 3 \][/tex]

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