Find the Products AB and BA to Determine Whether B $$A = \left[ \begin{array} { r r r r } 1 & - 2 & 0 & 0 \\0 & 1 & - 2 & 0 \\0 & 0 & 1 & 9 \\0 & 0 & 0 & 1\end{array} \right]$$

Multiple Choice

Find the products AB and BA to determine whether B is the multiplicative inverse of A.
- $$A = \left[ \begin{array} { r r r r } 1 & - 2 & 0 & 0 \\0 & 1 & - 2 & 0 \\0 & 0 & 1 & 9 \\0 & 0 & 0 & 1\end{array} \right]$$

A) $\left[ \begin{array} { c c c c } 1 & 2 & 4 & - 36 \\ 0 & 1 & 2 & - 18 \\ 0 & 0 & 1 & - 9 \\ 0 & 0 & 0 & 1 \end{array} \right]$

B)
$$\left[ \begin{array} { r r r r } 1 & - 9 & 18 & - 36 \\0 & 1 & 2 & - 4 \\0 & 0 & 1 & 2 \\0 & 0 & 0 & 1\end{array} \right]$$

C)
$$\left[ \begin{array} { r r r r } 1 & 0 & 0 & 0 \\- 9 & 1 & 0 & 0 \\18 & 2 & 1 & 0 \\- 36 & - 4 & 2 & 1\end{array} \right]$$
D)
$$\left[ \begin{array} { r r r r } 1 & 0 & 0 & 0 \\2 & 1 & 0 & 0 \\4 & 2 & 1 & 0 \\- 18 & - 18 & - 9 & 1\end{array} \right]$$