Which of the following formulae best demonstrates Boyle's Law of gases?

Boyle's Law relates the pressure and volume of a gas at a constant temperature, stating that the product of the pressure and volume of a gas is a constant value when the temperature remains unchanged. This relationship can be mathematically represented as P1 x V1 = P2 x V2, indicating that the initial pressure (P1) multiplied by the initial volume (V1) equals the final pressure (P2) multiplied by the final volume (V2).

This formula highlights that if the volume of a gas increases, the pressure must decrease, and vice versa, while keeping the temperature constant. It clearly illustrates the inverse relationship between pressure and volume in gas behavior under constant thermal conditions.

The other options present variations that do not correctly reflect Boyle's Law. For instance, configurations involving addition or division of pressure and volume do not accurately represent the direct proportionality and the constant nature described in Boyle's Law.