Please help i don't know this one

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

5cakes cost 3.50 how much do 7 cakes cost

Which of the following transformations will make coincide with ? a. counter-clockwise rotation 90º about a, followed by a translation 5 units to the right b. translation 5 units to the right, followed by a reflection across the y-axis c. translation 5 units to the right, followed by a reflection across the x-axis d. translation 1 unit up and 5 units to the right, followed by a reflection across the x-axis