Calculate the difference between two hour columns after below conditions have been met

I want to calculate the hours difference between Total Hours and orginal work hours which has date slicer .

Dax Query should be written as below and after this conditions have been met then have to calculate the difference between orginal workhours and Total hours

WHERE PROJ.Active = 1 AND TAR.ApprovalStatusID IN (5,7,8)

(TAE.OriginalWorkHours,0) != TAE.Total Hours

TAE.OriginalWorkHours is not null

TAR.ApprovalDateTime>DATEADD(s, -1, DATEADD(m, DATEDIFF(m, 0, @pendwkdate)+1, 0))

then difference between orginalworkhours-Totalhours

I am trying to write the conditions in Dax but its saying its incorrect