I have a column A7:A that has numbers from 1+;
I have another column B7:B, that has dates from Oct 31st, 2015 +;
I have a column F7:F that has weight values;
I have a goal weight of 108.36297798;
I need to find on what date from today will I reach my goal weight, but I only want to count values from the last 30 days on and not everything. This means that some dates may be empty but I want last 30 available values to be counted, so if it's empty go back until there's 30 values.
So far I've tried;
=DATEVALUE(TODAY() + ((108.36297798)-(INTERCEPT(F7:F,A7:A)))/(SLOPE(F7:F,A7:A)))
this just returns all the values, I want only last 30?