When a matrix is multiplied by a constant, the constant multiplies each of the elements of the matrix.
[tex] 2\left[\begin{array}{cc}4&0\\-1&5\end{array}\right]=\left[\begin{array}{cc}2\cdot 4&2\cdot 0\\2\cdot(-1)&2\cdot 5\end{array}\right]\\\\=\left[\begin{array}{cc}8&0\\-2&10\end{array}\right] [/tex]
