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QJEEM22Madbb6: JEE Main 2022 Mathematics - Class 11 JEEM22Madbb6 Solution: Let A be a 3 3 matrix having entries from the set { 1, 0, 1}.…

Let A be a 3 ×\times 3 matrix having entries from the set { −- 1, 0, 1}. The number of all such matrices A having sum of all the entries equal to 5, is ___________.

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Case-I:

1amp;→7 times  and −1amp;→2 times \begin{aligned} 1 & \rightarrow 7 \text { times } \\\\ \text { and }-1 & \rightarrow 2 \text { times } \end{aligned}

number of possible marrix =9!7!2!=36=\frac{9 !}{7 ! 2 !}=36

Case-II:

1→61 \rightarrow 6 times,

−1→1-1 \rightarrow 1 times

and 0→20 \rightarrow 2 times

number of possible marrix =9!6!2!=252=\frac{9 !}{6 ! 2 !}=252

Case-III:

1→51 \rightarrow 5 times,

and 0→40 \rightarrow 4 times

number of possible marrix =9!5!4!=126=\frac{9 !}{5 ! 4 !}=126

Hence total number of all such matrix AA =414=414

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