2x +5y +4z=28 3x- 2y+ 5z =19 6x + 3y - 2z=4 Tentukan nilai 2x -3y+z Tolong di jelas kan yah kk

2x + 5y + 4z = 28 ....(1)
3x - 2y + 5z = 19 ....(2)
6x + 3y - 2z = 4 .....(3)

pers (1) dan (2)
2x + 5y + 4z = 28 | 5 |
3x - 2y + 5z = 19 | 4 |
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10x + 25y + 20z = 140
12x - 8y + 20z = 76
_________________-
-2x + 33y = 64.....(4)


pers ( 1) dan (2)
2x + 5y + 4z = 28 | -1|
6x + 3y - 2z = 4 | 2 |
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-2x - 5y - 4z = -28
12x + 6y -4z = 8
_________________-
-14x - 11y = -36
14x + 11y = 36.....(5)

pers (4) dan (5)
-2x + 33y = 64 | 1 |
14x + 11y = 36 | 3 |
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-2x + 33y = 64
42x + 33y = 108
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-44x = -44
x= -44/-44
x=1


14x + 11y = 36
14(1) + 11y =36
11y = 36 - 14
11y = 22
y = 22/11
y = 2


2x + 5y + 4z = 28
2(1) + 5(2) + 4z = 28
2 + 10 + 4z = 28
12 + 4z = 28
4z = 28 - 12
4z = 16
z = 16/4
z = 4