E. -36

x + y + z = 5. pers 1

2x - 3y - 4z = -11. pers 2

3x + 2y - z = - 6. pers 3

pers 1 dan pers 2

x + y + z = 5. | x 2

2x - 3y - 4z = -11. | x 1

2x + 2y + 2z = 10

2x - 3y - 4z = -11 -

5y + 6z = 21. pers 4

pers 1 dan pers 3

x + y + z = 5. | x 3

3x + 2y - z = - 6 | x 1

3x + 3y + 3z = 15

3x + 2y -. z = -6 -

y + 4z = 21 pers 5

pers 4 dan pers 5

5y + 6z = 21. | x 1

y + 4z = 21 | x 5

5y + 6z = 21

5x +20z = 105 -

-14z = -84

z = -84 : -14

z = 6

y + 4z = 21

y + 4(6) = 21

y + 24 = 21

y = 21 - 24

y = -3

x + y + z = 5

x + ( -3) + 6 = 5

x + 3 = 5

x = 5 - 3

x = 2

maka

a x b x c = 2 x (-3) x 6 = -36

Jadi jawabanya adalah option E. (-36)