Which related equations are in the fact family 2+f=13

How do i do this activity, is appreciated

The input to the function is x and the output is y. write the function such that x can be a vector (use element-by-element operations). a) use the function to calculate y(-1.5) and y(5). b) use the function to make a plot of the function y(x) for -2 ≤ x ≤ 6.

What is the inverse of the function below? f(x)=x/3-2