Earlier, both Girolamo CARDANO in his Ars Magna (1580) and Hui YANG (of China, c.1238 - 1298) had used the same method of calculating determinants that Seki later used to find the root of pluralistic simultaneous linear equations with two unknown coefficients; Yang's findings were recorded in Xiangjie Jiuzhang Suanfa (a mathematical treatise in which Yang acknowledged that his method of finding square roots and cubic roots had been invented by another mathematician).