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Find unknown entries in a matrix equation

Question 1 of 8

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A school canteen recorded its sales over two weeks. The first matrix below shows the number of each item sold in Week 1, and the matrix on the right-hand side shows the total sold over both weeks. The matrix X records the Week 2 sales

In each matrix, the rows are Sandwiches, Muffins (top to bottom) and the columns are Recess, Lunch (left to right)

\begin{bmatrix} 1 & 7 \\ 7 & 2 \end{bmatrix} + X = \begin{bmatrix} 9 & 9 \\ 11 & 7 \end{bmatrix}