Answer
$(x,y,z)=(5t+2,2t-1,t)$; $t$ refers to a real number.
Work Step by Step
Consider $y-2z=-1 \implies y=2z-1$
Suppose $z=t$
This implies $y=2t-1$
Now, $x-3y+z=5 \implies x-3(2t-1)+t=5$
or, $x=5t+2$
Our result is : $(x,y,z)=(5t+2,2t-1,t)$; $t$ refers to a real number.