Final answer:
The function that represents shifting a function to the left one unit is f(x+1).
Step-by-step explanation:
When a function f(x) is shifted to the left one unit, the function that represents this transformation is f(x+1).
The transformation f(x+1) shifts the function to the left because when we substitute x+1 into the function, the result is that the x-values are each decreased by 1 compared to the original function.
For example, if the original function was f(x) = x^2, then the shifted function would be f(x+1) = (x+1)^2. This shifted function will have x-values one unit smaller than the original function.