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3 and 4 .Determinants and Matrices
normal
The number of $3 \times 3$ matrices $A$, whose entries are either $1$ or $-1$ and for which the system $A\left[ {\begin{array}{*{20}{c}}
x\\
y\\
z
\end{array}} \right] = \left[ {\begin{array}{*{20}{c}}
1\\
{ - 1}\\
0
\end{array}} \right]$ has exactly three distinct solutions, is
A
$0$
B
$2^9 - 1$
C
$168$
D
$2$
Solution
It is not possible that three planes intersect exactly at $3$ points . So no such matrix possible
Standard 12
Mathematics