Compute $A B$, if possible.
\[
A=\left[\begin{array}{rr}
0 & -3 \\
3 & 3
\end{array}\right] \text { and } B=\left[\begin{array}{rr}
-2 & 0 \\
-1 & 1
\end{array}\right]
\]

Step 1 ：We are given two matrices A and B, where A = \(\left[\begin{array}{rr} 0 & -3 \ 3 & 3 \end{array}\right]\) and B = \(\left[\begin{array}{rr} -2 & 0 \ -1 & 1 \end{array}\right]\).

Step 2 ：We are asked to compute the product of these two matrices, denoted as AB.

Step 3 ：The product of two matrices is computed by multiplying each element of the first row of the first matrix with the corresponding element of the first column of the second matrix and adding them up. This gives us the first element of the resulting matrix. We repeat this process for all the rows of the first matrix and all the columns of the second matrix.

Step 4 ：Let's denote the elements of the first matrix as \(a_{ij}\) and the elements of the second matrix as \(b_{ij}\). Then, the elements of the resulting matrix C will be: \(c_{11} = a_{11}b_{11} + a_{12}b_{21}\), \(c_{12} = a_{11}b_{12} + a_{12}b_{22}\), \(c_{21} = a_{21}b_{11} + a_{22}b_{21}\), \(c_{22} = a_{21}b_{12} + a_{22}b_{22}\).

Step 5 ：By substituting the given values into these formulas, we find that the resulting matrix C is \(\left[\begin{array}{rr} 3 & -3 \ -9 & 3 \end{array}\right]\).

Step 6 ：\(\boxed{C=\left[\begin{array}{rr} 3 & -3 \ -9 & 3 \end{array}\right]}\) is the final answer.