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Matrices [tex]$C$[/tex] and [tex]$D$[/tex] shown below are equal.

[tex]\[
C=\left[\begin{array}{cccc}
4 & -3 & 8 & 9.2 \\
1.2 & -6 & 5 & 1 \\
6 & 0 & -7 & 23
\end{array}\right]
\quad
D=\left[\begin{array}{llll}
d_{11} & d_{12} & d_{13} & d_{14} \\
d_{21} & d_{22} & d_{23} & d_{24} \\
d_{31} & d_{32} & d_{33} & d_{34}
\end{array}\right]
\][/tex]

What is the value of [tex]$d_{33}$[/tex]?

A. [tex]$-7$[/tex]
B. [tex]$-6$[/tex]
C. 5
D. 8


Sagot :

To solve this problem, we need to recognize the property that matrices [tex]\( C \)[/tex] and [tex]\( D \)[/tex] are equal. When two matrices are equal, their corresponding entries are also equal. This means that for any element [tex]\( c_{ij} \)[/tex] in matrix [tex]\( C \)[/tex], it must be equal to the corresponding element [tex]\( d_{ij} \)[/tex] in matrix [tex]\( D \)[/tex].

Given matrix [tex]\( C \)[/tex]:

[tex]\[ C = \left[ \begin{array}{cccc} 4 & -3 & 8 & 9.2 \\ 1.2 & -6 & 5 & 1 \\ 6 & 0 & -7 & 23 \end{array} \right] \][/tex]

And the corresponding matrix [tex]\( D \)[/tex]:

[tex]\[ D = \left[ \begin{array}{cccc} d_{11} & d_{12} & d_{13} & d_{14} \\ d_{21} & d_{22} & d_{23} & d_{24} \\ d_{31} & d_{32} & d_{33} & d_{34} \end{array} \right] \][/tex]

We are asked to find the value of [tex]\( d_{33} \)[/tex], which is the element in the 3rd row and 3rd column of matrix [tex]\( D \)[/tex].

Looking at the same position in matrix [tex]\( C \)[/tex], the element is:

[tex]\[ C[2][2] = -7 \][/tex]

Since [tex]\( C \)[/tex] and [tex]\( D \)[/tex] are equal, the value of [tex]\( d_{33} \)[/tex] will be the same as the value at [tex]\( C[2][2] \)[/tex].

Hence, the value of [tex]\( d_{33} \)[/tex] is:

[tex]\[ d_{33} = -7 \][/tex]

Therefore, the correct answer is:
[tex]\[ -7 \][/tex]