Is there any possiblities to take dependents after getting my student visa?
Yes it is possible
I do not have good grades in my graduation 48 percent, can I pursue masters from US in business? which university?
Grades do play an important role in pursuing masters in USA , though there are universities which look into holistic profile of the student , GMAT & IELTS score ,also work experience will be added advantage for Business course
What if student visa is rejected Australia?
Generally at IDP we have a high visa success rate