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Problem 9 - Entrance Test

What is the value of the determinant of the following matrix? [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

Correct: C

The determinant is 1(5*9 - 6*8) - 2(4*9 - 6*7) + 3(4*8 - 5*7) = 1(45 - 48) - 2(36 - 42) + 3(32 - 35) = -3 - 2(-6) + 3(-3) = -3 + 12 - 9 = 0.