The determinant of a 3times3 matrix is calculated as:det=a(ei−fh)−b(di−fg)+c(dh−eg)Where the matrix is:[abcdefghi]|205463891| = 2(6 - 27) - 0(4 - 24) + 5(36 - 48)= 2(-21) - 0 + 5(-12)= -42 + 5(-12)= -42 - 60= -102