berapakah hasik dari x+y+z=75 x-y-z=5 x-4y+z=0 tolong yg bisa

x+y+z=75
x-y-z=5
x-4y+z=0

.
x+y+z=75
x-y-z=5
------------- --
2y + 2z = 70

.
x-y-z=5
x-4y+z=0
-------------- --
3y - 2z = 5
.

2y + 2z = 70
3y - 2z = 5
---------------- +
5y = 75
y = 75/5
y = 15

.
2y + 2z = 70
2(15) + 2z = 70
30 + 2z = 70
2z = 70 - 30
2z = 40
z = 40/2
z = 20

.
x+y+z=75
x + 15 + 20 = 75
x + 35 = 75
x = 75 - 35
x = 40

jadi x = 40, y = 15, z = 20