How to Subtract Dates in LINQ?

Hi Friends...

I had came across a query, where i have to find the FirstName, LastName, Age from Employee table who are managers and their age is above 30.

Now in my Employee table, i have the columns--
EmployeeID(int)
FirstName(string?)
LastName(string?)
BirthDate(DateTime?)
HireDate(DateTime?)

Now i want help to write the query to get the years after subtracting BirthDate from the current date..

Thanks

G. S.
.Net Developer