So far we have learned/remembered
When asked 𝑓−1𝑐, 𝑐 is the output (𝑦-value) of 𝑓 and we need to find the corresponding input (𝑥-value) of 𝑓.
Comparing graphs of 𝑓 and 𝑓−1, the role of 𝑥 and 𝑦 swap
The point 𝑎,𝑏 becomes the point 𝑏,𝑎
Domains become ranges, ranges become domains
Horizontal asymptotes 𝑦=# become vertical asymptotes 𝑥=# 
Comparing graphs of 𝑓 and 𝑓−1, they look like reflections of each other over the line 𝑦=𝑥.