Find slope where changes in X are dates

[lilybickel]

Hi everyone,
Is it possible to find a gradient where the changes in X are dates?

I have attached an example database to show the set up I am working with: essentially I need the green section at the end of the table to output the gradients of change in Variables A, C, and E between Date X and Date Y or Date Z (only if there is no Date Y) for each row.

Date 1 corresponds to Variable-A 1, Variable-C 1 and Variable-E 1 and Date 2 corresponds to Variable-A 2, Variable-C 2 and Variable-E 2 etc.
For all Dates 1-5 that are >= Date X and <= Date Y then I want both the dates and corresponding variables to be included in a calculation that will find the gradient of each variable's change in relation to the dates they were recorded.

Any ideas on how to do this??
Thanks