 Solution

ID: past-exam-of-the-mathematics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2001/paper-2/7/a/i/solution

The two-by-two determinant is the difference of the diagonal products:

8513 = 8 \cdot 3 - 1 \cdot 5 = 19.

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