Adentist is making identical cards bags for patients

Which expression is equivalent to (9x - 3 1/ + 1 3/8)

Two airplanes start at the same place and travel in opposite directions, one at 395 miles per hour and the other at 422 miles per hour. how many hours will it take for the planes to be 2451 miles apart?

What adds to be the bottom number but also multiplies to be the top number with 8 on the bottom and 15 on top