Question

If $\left[\begin{array}{cc}xy& 4\\ z+6& x+y\end{array}\right]=\left[\begin{array}{cc}8& w\\ 0& 6\end{array}\right]$, write the value of (x + y + z).

Answer 1

$$\begin{gathered} \left[\begin{array}{cc}xy& 4\\ z+6& x+y\end{array}\right]=\left[\begin{array}{cc}8& w\\ 0& 6\end{array}\right] \\ \mathrm{Corresponding}\mathrm{elements}\mathrm{of}\mathrm{equal}\mathrm{matrices}\mathrm{are}\mathrm{equal}. \\ \therefore z+6=0\mathrm{and}x+y=6 \\ \Rightarrow z=-6\mathrm{and}x+y=6 \\ \mathrm{Therefore},x+y+z=6-6=0. \end{gathered}$$