Răspuns :
stiim ca: x + y = 700
y + z = 500
x + z = 800
------------------------- adunate , obtinem
2(x+y+z) = 2000 | :2
x + y + z = 1000 => 700 + z = 1000 deci z = 300 ;
=> y + 800= 1000 -,,- y = 200 ;
=> x + 500= 1000 -,,- x = 500 ;
y + z = 500
x + z = 800
------------------------- adunate , obtinem
2(x+y+z) = 2000 | :2
x + y + z = 1000 => 700 + z = 1000 deci z = 300 ;
=> y + 800= 1000 -,,- y = 200 ;
=> x + 500= 1000 -,,- x = 500 ;
2x(x+z+y)=700+500+800=2000
x+z+y=2000:2=1000
x+y=700
z=1000-700=300
y=500-300=200
x=800-300=500
x+z+y=2000:2=1000
x+y=700
z=1000-700=300
y=500-300=200
x=800-300=500