Brahmagupta (628 CE) started the systematic study of indefinite quadratic equations—in particular, the misnamed Pell equation, in which Archimedes may have first been interested, and which did not start to be solved in the West until the time of Fermat and Euler.
Brahmagupta (628) comezou o estudo sistemático das ecuacións cadráticas indefinidas, en particular a mal chamada ecuación de Pell, das que Arquímedes debeu ser o primeiro en interesarse, e que non comezaron a ser resoltas en occidente ata a época de Fermat e Euler.