1/2*x-y=1/3*x
y=x5/6①
x-y-1=z②
4x-5y+3z=5③
①带入②得
x-5/6x-1=z
z=x/6-1④
①④带入③
4x-5*(5x/6)+3(x/6-1)=5
4x-25x/6+x/2-3=5
1/3x=8
x=24
y=20
z=3