Question: Given the following matrices, perform the indicated operation, if possible.
A = [ 9 -2 -1
-8 0 -3 ], B = [ 1 0
-7 8 ], C = [ 3 3 -2
7 2 -2
-6 -8 2 ], and D = [ -6 8
-3 1
6 -7 ]
B + AD
Select the correct choice and, if necessary, fill in the answer box to complete your choice.
A. B + AD =
B. The matrix product is not defined.
1. **State the problem:** We need to find the matrix sum $$B + AD$$ if it is defined.
2. **Check dimensions:**
- Matrix $$A$$ is $$2 \times 3$$.
- Matrix $$D$$ is $$3 \times 2$$.
- Matrix $$B$$ is $$2 \times 2$$.
3. **Matrix multiplication feasibility:**
- The product $$AD$$ is defined if the number of columns of $$A$$ equals the number of rows of $$D$$.
- $$A$$ has 3 columns, $$D$$ has 3 rows, so $$AD$$ is defined.
- The resulting matrix $$AD$$ will be $$2 \times 2$$.
4. **Calculate $$AD$$:**
$$
AD = \begin{bmatrix}9 & -2 & -1 \\ -8 & 0 & -3\end{bmatrix} \times \begin{bmatrix}-6 & 8 \\ -3 & 1 \\ 6 & -7\end{bmatrix}
$$
Calculate each element:
- First row, first column:
$$9 \times (-6) + (-2) \times (-3) + (-1) \times 6 = -54 + 6 - 6 = -54$$
- First row, second column:
$$9 \times 8 + (-2) \times 1 + (-1) \times (-7) = 72 - 2 + 7 = 77$$
- Second row, first column:
$$-8 \times (-6) + 0 \times (-3) + (-3) \times 6 = 48 + 0 - 18 = 30$$
- Second row, second column:
$$-8 \times 8 + 0 \times 1 + (-3) \times (-7) = -64 + 0 + 21 = -43$$
So,
$$
AD = \begin{bmatrix}-54 & 77 \\ 30 & -43\end{bmatrix}
$$
5. **Add $$B + AD$$:**
$$
B = \begin{bmatrix}1 & 0 \\ -7 & 8\end{bmatrix}
$$
Add element-wise:
- Top-left: $$1 + (-54) = -53$$
- Top-right: $$0 + 77 = 77$$
- Bottom-left: $$-7 + 30 = 23$$
- Bottom-right: $$8 + (-43) = -35$$
So,
$$
B + AD = \begin{bmatrix}-53 & 77 \\ 23 & -35\end{bmatrix}
$$
6. **Conclusion:** The matrix product $$AD$$ is defined and the sum $$B + AD$$ is:
$$
\boxed{\begin{bmatrix}-53 & 77 \\ 23 & -35\end{bmatrix}}
$$