Dr. george is ready to by a new iphone and has two different carriers he can go with. cell 4 u can be represented by the function c(x)=10x+75. data house can be represented by the function c(x)=15x+50. x represents the amount of data used. accessories will cost $135 dr. george usually uses 4 gigs of data a month.

1. how much will the phone cost at cell 4u?

2. how much will the phone cost at data house?

3. which company should dr. george go with? justify your answer.