Mounting large tv to drywall
No... those expanding bolts aren't going to do the job, period. There are several reasons but suffice it to say your TV will find up on the floor.  Toggle bolts of some variety are the preferred way to do it... it's hard to believe that no one in a city the size of yours has them or something more suitable.  What you need is something that will spread the weight of your TV over a wide enough surface area and not be dependent on resisting withdrawal through the sheetrock, as the ones you pictured are.  You said you can't find the studs... how have you tried?  Is your home typical studs with sheetrock over?  If they are metal studs that might be why you're having so much trouble.  But don't use what you have pictured, they are not suitable.  Let me know your answers to the above and I'm sure we can figure this out.