Hello guys, can someone help me with this question please?
$\displaystyle M=\left(\begin{array}{cccc} a & b & c & d \\ x & y & z & w \\ t & r & s & u \\ m & n & p & q\end{array}\right)$
$\displaystyle |M|=3$
$\displaystyle Q=\left(\begin{array}{cccc} 2 a & 10 b & 2 c & 2 d \\ x & 5 y & z & w \\ -t & -5 r & -s & -u \\ m & 5 n & p & q\end{array}\right)$
$\displaystyle |Q| = -10|M| = -30$