Question

If $\Delta =\left|\begin{array}{ccc}6i& -3i& w\\ 4& 3i& -w\\ 20& 3& iw\end{array}\right|=x+iy$, then

• A. $x=3,y=1$
• B. $x=1,y=3$
• C. $x=0,y=3$
• D. $x=0,y=0$

Answer 1

Answer: (D)

We can write
$\Delta =-3iw\left|\begin{array}{ccc}6i& 1& 1\\ 4& -1& -1\\ 20& i& i\end{array}\right|=0$
$\therefore x=0,y=0$