From second equation we getOriginally Posted byNatasha1

z=x+y-12

In third equation we replace z

x-y+x+y-12=16

2x=28

x=14

So we get now

y+z=10

y-z=-2

-y+z=2

From second equation we get y=z-2

We replace y in first equation

z-2+z=10

2z=12

z=6

So we have x=14 and z=6 so we get that y=4.

So x-y-z=14-4-6=4.