Answer:
x=8.94 ; y = 1.58; z=2.02
Explanation:
solve 10x+4y+12z = 120 → 5x+2y+6z = 60
8x + 2y +32Z = 160 → 4x+y+16z = 80
To eliminate z multiply first equation by 16 and second equation by 6.
80x+32y+96z = 960
24x+6y+96z = 480
on subtractionwe get 56x+26y = 480
dividing by 2 we get, 28x + 13y = 240
Now we have a given equation 11x + 77y = 220 → x + 7y = 20
solving 28x + 13y = 240 and x + 7y = 20
28x + 13y =240
28x + 216y = 560
subtracting we get, 203y = 320
y = 1.58
x = 8.94
z = 2.02