Question

2x-y-4z=-4,x+3y-z=-8,-4x+2y+3z=-2

Answer 1

2x - y - 4z = -4 ...(1)
x + 3y - z = -8 ...(2)
-4x + 2y + 3z = -2 ...(3)

kalikan 2 persamaan 1
4x - 2y - 8z = -8
persamaan 3
-4x + 2y + 3z = -2
_______________+
-5z = -10
z = -10/(-5) = 2

kalikan 3 persamaan 1
6x - 3y - 12z = -12
persamaan 2
x + 3y - z = -8
____________+
7x - 13z = -20
7x - 13 . 2 = -20
7x - 26 = -20
7x = -20 + 26
7x = 6
x = 6/7

substitusi ke persamaan 2
x + 3y - z = -8
6/7 + 3y - 2 = -8
-8/7 + 3y = -8
3y = -8 + 8/7
3y = -48/7
y = -48/7 . 1/3 = -16/7