First I thing you mean 34 not 43 but that is not the problem.
From the second equation we
x tan 34 =z
Substitute that into first equation,
tan 30=z/(1500+z/(tan 34))
This is a regular equation for z.
Alterntiely you can dived your equations,
tan 30/tan 34=x/(1500+x)
Solve for x,
Then solve for z