Question

Bantuu jawab dongg poinnya 40
hitunglah determinan matriks berikut dengan cara baris ketiga

Answer 1

Verified answer

M31 = |2 .. 5| = 2(6) - (-3)(5) = 12 + 15 = 27
............|-3 ..6|
C31 = (-1)^(3 + 1) . M31 = (-1)^4 . 27 = 27

M32 = |7 ... 5| = 7(6) - 4(5) = 42 - 20 = 22
.............|4 .. 6|
C32 = (-1)^(3 + 2) . M32 = (-1)^5 . 22 = -22

M33 = |7 ... 2| = 7(-3) - 4(2) = -21 - 8 = -29
............|4 ... -3|
C33 = (-1)^(3 + 3) . M33 = (-1)^6 . -29 = -29

determinan dengan kontaktor baris ke 3
det = a31 . C31 + a32 . C32 + a33 . C33
= -1 (27) + 1 (-22) + 4 (-29)
= -27 - 22 - 116
= -165