Analysis :: SSAS 2012 - MDX To Find Last 7 Days Data In Where Clause?

I have a MDX query , where I have a date Range in where clause.

I want to replace it with Cuurent Date and Last 7 days date.

I tried multiple ways using NOW function , but could not get it correct .

modifying the Query so that I can fetch DATA for last 7 days 

SELECT NON EMPTY { [Measures].[X] } ON COLUMNS, NON EMPTY { ([PRODUCT].[PRODUCT].[PRODUCT].ALLMEMBERS ) } DIMENSION PROPERTIES MEMBER_CAPTION, MEMBER_UNIQUE_NAME ON ROWS
FROM ( SELECT ( { [COLOR].[COLORName].&[BLACK], [COLOR].[COLORName].&[BLUE] } ) ON COLUMNS
FROM ( SELECT ( [Date].[Calendar].[Calendar Year].&[2015].&[2015]&[3].&[7].&[20150706] : [Date].[Calendar].[Calendar Year].&[2015].&[2015]&[2].&[6].&[20150629] ) ON COLUMNS
FROM [MYCUBE]))

I want to replace Date Hard code value , I have used Calendar Hierarchy of date dimension. to find Last 7 days Data.