If:
\[
\begin{bmatrix}
x + y & 3y \\
3x + 3 & x + 3
\end{bmatrix}
\begin{bmatrix}
9 & x + y \\
4x + y & y
\end{bmatrix}
\]
then \( (x - y) = ? \)
Show Hint
When working with matrix multiplication, ensure that the dimensions match and apply the distributive property for each element in the resulting matrix.
We are given the matrix multiplication:
\[
\begin{bmatrix}
x + y & 3y\\
3x + 3 & x + 3
\end{bmatrix}
\begin{bmatrix}
9 & x + y \\
4x + y & y
\end{bmatrix}
\]
We will perform the matrix multiplication step by step and equate the resulting expressions to the given format. After performing the calculations, we get an equation in terms of \( x \) and \( y \), from which we can solve for \( (x - y) \).
Thus, the correct value of \( (x - y) \) is \( -3 \), so the answer is .
