A 775 mL sample of NO2 is at STP. if he volume changes to 615 mL and the temperature changes to 25.0, what will be the new pressure in ATM?

Yes you can use that 1 equation ... P1V1 / (n1T1) = P2V2 / (n2T2) for ALL of your two state ideal gas law type problems. Use it in place of boyles, charles, avogadros, combined, etc laws ... just like I showed you above

(1) ... write down P1V1 / (n1T1) = P2V2 / (n2T2)

(2) ... rearrange for your desired unknown

(3) ... determine what is constant and what varies ... cancel the constants

(4) ... plug and chug ... don't forget Temperature must be on an absolute scale ... R or K ... never °F nor °C