Being able to solve a system of equations is definitely not "new" mathematics. Mahāv1̄ra, the best-known Indian mathematician of the 9th century, worked the following problem. See if you can solve it.
The mixed price of 9 citrons and 7 fragrant wood apples is 107; again, the mixed price of 7 citrons and 9 fragrant wood apples is 101. O you arithmetician, tell me quickly the price of a citron and of a wood apple here, having distinctly separated those prices well?