Question

x+y+z=7 x,yz+y,zx+z,xy=?, acelea sunt cu bara sus, raspuns rapid, va rog!

Answer 1

x+y+z=7
xyz/100+yzx/100+zxy/100=
(xyz+yzx+zxy)/100=
xyz=100x+10y+z
yzx=100y+10z+x
zxy=100z+10x+y
[100(x+y+z)+10(x+y+z)+(x+y+z)]/100
111(x+y+z)/100=
111•7/100=
777/100=
7,77
x=2
y=1
z=4
2,14+1,42+4,21

Answer 2

X+y+z=7 x,yz+y,zx+z,xy=?

x,yz = xyz/100 
y,zx = yzx/100
z,xy = zxy/100

xyz/100 + yzx/100 + zxy/100 =

=  ( 100 x + 10 y + z + 100y + 10z + x + 100 z + 10 x  + y ) /100 =

= ( 111 x + 111 y + 111 z ) /100 =

= 111 × ( x + y + z ) /100 =

= (111 × 7 ) /100 =

= 777/100 =

= 7,77 

Raspuns:   x,yz + y,zx + z,xy = 7,77