Tentukan x,y,dan z dari sistem persamaan x+y+z=75 X-y-z=5 X-4y+z=0 Tolong yaa kawan pliss

operasi eliminasi 1,
x + y + z = 75
x - y - z = 5
——————— -
0 + 2y + 2z = 70

operasi eliminasi 2,
x + y + z = 75
x - 4y + z = 0
——————— -
0 + 5y + 0 = 75
5y = 75
y = 15

maka,
2y + 2z = 70
(2 X 15) + 2z = 70
2z = 70 - (2 X 15)
2z = 70 - 30
2z = 40
z = 20

maka,
x - y - z = 5
x - 15 - 20 = 5
x = 5 + 15 + 20
x = 40

sehingga x = 40, y = 15, dan z = 20