Respuesta :
1........x+y+z=65
2........x=2y
65-(x+y)=z
x+y=65-z
3.......20x+5y+10z=875
20(2y)+5y+10z=875
45y+10z=875
z=(875-45y)/10
2y+y+(875-45y)/10=65
30y+875-45y=650
-15y=-225
y=15
x=30
z=20
2........x=2y
65-(x+y)=z
x+y=65-z
3.......20x+5y+10z=875
20(2y)+5y+10z=875
45y+10z=875
z=(875-45y)/10
2y+y+(875-45y)/10=65
30y+875-45y=650
-15y=-225
y=15
x=30
z=20