Let's assume
independent variable is x
dependent variable is h
A linear function h models a relationship in which the dependent variable increases 1 unit for every 5 units the independent variable decreases.
so, we can use formula of linear function

where
m is slope

now, we can plug values

The value of the function at 0 is 3
so, at x=0 , h=3
we can use it and find b


now, we can plug back

now, we can draw graph
Graph: