Domain means the values that can be used as a function's input. Since all real values of x will yield a real value of f(x), the domain is (-infinity, infinity).
You are given the function 
Express t:

This expression gives the month t in terms of the price p.
2/3 + 1/2 is 7/6
Hope this helps!
sometimes i use a thingy called calculator soup and it should have a measurement calculator