Let $A$ and $B$ be the following matrices.

$$A = \left[\begin{array}{cccc} -6 &1 &-6 &5 \end{array}\right], \qquad B = \left[\begin{array}{c} 9\cr 1\cr -5\cr 4 \end{array}\right]$$

Perform the following operation:

$B \cdot A =$ $\left[\Rule{0pt}{4.8em}{0pt}\right.$$\left]\Rule{0pt}{4.8em}{0pt}\right.$