y-z=35 ,y=35+z -------[1]
y-x=5 -------[2]
x+y+z=180 -----[3]
[1]-[2]:x-z=30,x=30+z
代入[3]：
30+z+35+z+z=180,z=115/3
x=90/3+115/3=205/3
y=105/3+115/3=215/3