Answer: Choice A
[tex]\begin{pmatrix}-15 & 59 & -3\\16 & 61 & -83\\-45 & -99 & 106\end{pmatrix}[/tex]
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Explanation:
In matrix A, the upper left corner is -3
Multiply this with -7 to get -7*(-3) = 21
So we'll have 21 in the upper left corner of matrix -7A. The other entries will be handled in a similar fashion.
Meanwhile, the upper left corner of matrix B is 9. Multiply this with -4 to get 9(-4) = -36 which is the upper left corner entry of matrix -4B
Combine those products: 21 + (-36) = -15
The number -15 is the upper left corner entry in matrix -7A-4B
This points us to choice A as the final answer.
