[QUOTE=CRGreathouse;1606846]Al-Khwarizmi certainly solved equations with general methods, but as he was later than Brahmagupta it is less of a credit to him. I'll admit, I know of no Greek nor Chinese general equation solvers until modern times, but that could easily be my lack of knowledge in the subject. I'm not much into math history.
Brahmagupta never solved any cubic or quartic using general methods. Brahmagupta, Bhaskara and Mahavira used special ad hoc methods to solve such equations if need arises.
Solving equations using general methods first done by Aryabhatta since he solved linear indeterminate equations using general methods. I was wrong to say it was Brahmagupta who solved the quadratic using general methods.