I think I have got a good handle on how to manipulate linear to linear fxns but this is totally stumping me. Tell me what I'm doing wrong?

For each of the following, find the linear function f(x) satisfying the given requirements.

1. f(0)=0

2. f(10)=10

3. f(20)=16

I am taking f(0) to mean y=0 when x=0

f(10)=10 when x=10 and y=10

f(20)=16 when x=20 and y=16

So I enter the points in y=ax+b/x+d and solve for a,b, and d.... right?