Which quantity is held constant when working with boyle’s, charles’s, and gay-lussac’s laws?
volume
moles
pressure
temperature

Moles

Explanation:

Boyle's law:

Boyle's law stated that volume and pressure are inversely proportional to each others by keeping the number of moles and temperature constant.

Mathematical expression:

P₁V₁ = P₂V₂     (n and T are constant)

Charles's law:

Charles's law stated that temperature and volume are directly related related to each others by keeping number of moles and pressure constant.

Mathematical expression:

V₁/T₁ = V₂ /T₂   (n and P are constant)

Gay-Lussac's law:

This law stated that pressure of gas is directly related to its temperature by keeping the number of moles and volume constant.

Mathematical expression:

P₁/T₁ = P₂ /T₂   (n and V are constant)

it's filtration, but this is an assumption so my apologies if i got this