Question
Question: \[\left| \begin{matrix} 1 & 1 & 1 \\ 1 & 1 + x & 1 \\ 1 & 1 & 1 + y \end{matrix} \right| =\]...
1 & 1 & 1 \\
1 & 1 + x & 1 \\
1 & 1 & 1 + y
\end{matrix} \right| =$$
A
1
B
0
C
x
D
xy
Answer
xy
Explanation
Solution
$\left| \begin{matrix} 1 & 1 & 1 \ 1 & 1 + x & 1 \ 1 & 1 & 1 + y \end{matrix} \right| = \left| \begin{matrix} 0 & 0 & 1 \
- x & x & 1 \ 0 & - y & 1 + y \end{matrix} \right| = xy,$
C1→C1+C2+C3.