# Replacing \$x,y\$ in \$f(x,y,z)\$ with values from a list

I’m sure there is a simple solution to this using map or apply, but its not occurring to me.

Suppose I have a function $$f(x,y,z)= x+y+z)$$

And I want to evaluate $$f(x,y,1)$$ for $$\{x,y\} ∈ \{\{1,2\},\{3,4\}\}$$

What is the best way to do this?

Examples:

If I use `f[x_,y_,z_]:= x+y+z; f[#1,#2,1]&/@ {{1,2},{3,4}}`

this will give me things like `{{2+#2,3+#2}}.`

On the other hand, `Apply` works on a single element `f[#1,#2,1]& @@ {1,2}` but not on a list such as `{{1,2},{3,4}}`. On the list it gives me `{f[1,3,1],f[2,4,1]`

I am not sure how to go from the case of a single pair to a list of pairs