when to use each equation

[Kaethe Zappacosta 2L]

I am confused on when we use w=-pdeltaV versus w=-nRTln(Vf/Vi)?

[Jeffrey Yang 3I]

These two equations relate to what values are constant in the scenario. If the pressure is constant, you can remove it from the integral to have w = -p*deltaV. If the temperature is constant, you can replace pressure with nRT, and pull this out from the integral because it is constant. When you integrate 1/V, you have the ln(Vf/Vi) term.

[Harsimer Bal 3K]

When work equals -PdeltaV, the external pressure of a system is constant during expansion in a system. This equation is used for an irreversible process as the expansion is a measurable amount of change that cannot be reversed rather than many infinitesimal changes to a variable. Work is equal to -nRTln(V2/V1) for the reversible, isothermal expansion of an ideal gas. The temperature remains constant and the pressure of the gas falls as it expands so the external pressure must be reduced to match the pressure of the gas with each step.

[Maggie Clark]

I would see what is given in the problem, and plug that in