please check and correct if needed. thanks

problem:
you have coupon of $50 off your telephone purchase of $100 or more at bell store.
a. write a function relating phone purchase price after coupon, y, to the retail price, x . give the domain of this function
i wrote y => (100x - $50)
domain x=> 100

b. online offer of 40% discount off phone retail price x write a functio relating a phone purchase price , y, to the retail price , x, give the domain
f/y = x - {(x) times 40}
domain x > 0
thanks ann

2 answers

a. y= x-50 if x>100, y=x if 0<x<99.99

b. y=.6x yours is the same thing.
Bob, thank you very much for your help. ann