Excel 2003 days before a certain date [Solved]

Hello,
I am making a spreadsheet which has, for example, a given date of 1/1/2012.
When I enter that number into cells A1, I want it to return a date 105 days prior in to cell E1, and 45 days prior than the given date. But...this formula will only be applicable if the cell value in B1 is "SE".
thank you sooo much