Why does gcd not change when with multiples of numbers?

Erin bought christmas cards for $2 each to send to her family and friends. which variable is the dependent variable?

What is the slope of the line? a. -5/2 b.2/5 c. 5/2 d.7/2

The water aquarium shark tank is always greater than 25 feet of the water level decreased by 6 feet during cleaning what was the water level before the cleaners took out any water