Can I study 2 level 3 courses at collegeWatch
BTEC Extended Certificate = 1 A level, BTEC Extended Diploma = 3 A levels.
So if you do the Extended Diploma plus another subject at Extended Certificate then you are doing the equivalent work of 4 A levels. This is 'doable' if the school/college let you and can make the timetable work, however you need to think about why you want to do this. Would you be better just doing an Extended Diploma in Business to keep more doors open to you?