I want to get records last modified date is > 7.
like if(audList.LastModifiedDate > (Date.today() - 7)){
Can we do this with date literal?
If your question is related to SOQL queries, its possible. There is a query literal
LAST_N_DAYS:n
With this you can achieve your requirement.
For example, if your date field is MyDateField, your query condition becomes
MyDateField >= LAST_N_DAYS:7
N_DAYS_AGO:x
. All of the 'relative date values' listed in Relative Date Values for Filter Criteria should work just fine in SOQL as well.