Diophantus' previous reference was discussed more explicitly by Indian mathematician Brahmagupta, in Brāhmasphuṭasiddhānta in 628, who used negative numbers to produce the general form quadratic formula that remains in use today.
Tihza hintokayat ən Dioɗhante təmədash tənna təjet as awmadinan ən Inde Brahmaguɗta, dǎɣ Brāhmasɗhuțasiddhānta ɣor 628, itkalən imaɗinan ədarətnen ye iji ən iri quadratique ən ini niyan aqimən ijan ashali.