Find the value of each variable

x=15; y=45
x=25; y=75
x=30; y=90
x=40; y=120

Closing a credit card usually _your debt ratio.a. increasesb. decreasesc. improvesd. has no effect on

Fanny mendelssohn manages all the magazines and paperback books at a local grocery store. she prices many paperbacks to sell at $7.99. the cost to the store is $5.29. what is the markup rate on a paperback book, based on its cost?

Math i have no idea how to do a and b