How to update parent records when task is created or updated in Salesforce?

Below sample trigger can be used to update parent records when task is created or updated.
 
Note:
I have implemented the trigger to update Opportunity alone. It do a dummy update as I have used just Id in the update DML Operation.

Sample Trigger:

trigger TaskTrigger on Task (after insert, after update) {

    Set < Id > setOpptyIds = new Set < Id >();
    
    for ( Task t : trigger.New) {
    
        if ( t.WhatId.getSobjectType().getDescribe().Name == 'Opportunity' ) {
        
            setOpptyIds.add(t.WhatId);
        
        }
    }
    
    if ( setOpptyIds.size() > 0 ) {
    
        List < Opportunity > listOppty = new List < Opportunity >();
        
        for ( Id opptyId : setOpptyIds ) {
        
            listOppty.add(new Opportunity(Id = opptyId));
            
        }
        
        update listOppty;
        
    }
    
}
 
Trigger to update all the object records when the Task is created or updated:
trigger TaskTrigger on Task (after insert, after update) {

    Set < Id > setRecIds = new Set < Id >();
    
    for ( Task t : trigger.New) {
    
        if ( String.isNotBlank( t.WhatId ) ) {
        
            setRecIds.add(t.WhatId);
        
        }
    }
    
    if ( setRecIds.size() > 0 ) {
    
        List < sObject > listRecs = new List < sObject >();
        
        for ( Id recId : setRecIds ) {
            
            sObject obj = recId.getSObjectType().newSObject( recId );
            listRecs.add( obj );
        
        }
        
        update listRecs;
        
    }
    
}