Calculating a function variable for a specific output

I have a function which depends on 3 variables.

Lets say my function is this:

Tend=@T(x,y,z)

Assume that the variables x and y are known. How can I calculate the z value for a specific Tend value?

Answer 1

[John D'Errico]

You will need a guess for z. I'll call it z0.

zsolve = fzero(@(z) T(x,y,z) - Tend,z0);