// minds behind maths

Brahmagupta

598–668 CE · Algebra, arithmetic

In the Brahmasphutasiddhanta (628 CE) he gave the first systematic rules for arithmetic with zero and with negative numbers, framing them in terms of 'fortunes' and 'debts'. He also gave a formula for the area of a cyclic quadrilateral that bears his name.

Source: MacTutor — Brahmagupta

Formulas that trace back to Brahmagupta

(a+b)² − (a−b)² = 4ab (a+b)² - (a-b)² = 4ab

(x+a)(x−a) (x+a)(x-a) = x² - a²

Difference of Two Squares a²−b² a² - b² = (a-b)(a+b)

General Difference of Squares A²−B² A² - B² = (A-B)(A+B)