History of Hindu Mathematics: A Source Book v2.c17.s26.16

v2.c17.s26.16

The reference in the latter portion of this rule is to the method of the unknown writer. The principle underlying Brahmagupta's method is to reduce, like the Greek Diophantus (*c.* 275),¹ the given indeterminate equation to a simple determinate one by assuming arbitrary values for all the unknowns except one. So it is undoubtedly inferior to the earlier method. Brahmagupta gives the following illustrative example: