So here is the system:

V+W+X+Y+Z=7

X+2y+3z=8

x+2y+5z=10

I used Gaussian elimination method and got this:

V+W+X+Y+Z=7

X+2Y+3Z=8

-2Z=-2

So from here I can get z=1 but couldn't go up from here as the next equation (x+2y+3z)=8 has two other unknowns and the other is even worse with 5 variables. Anyone help please?