You are in the market for a new phone company to switch to because your current one is going out of business. You have done your research and you have narrowed your choice down to two companies who bill monthly. New Phone Who Dis Inc. has a unlimited text plan that costs $50 a month for unlimited texting, plus $4 per phone call that you make.

Talk More Worry Less also has an unlimited text plan, but theirs will cost you $9 a phone call.

Which equations represent the two companies?

a. y = 50x + 4
b. y = 50 + 4x
c. 50 +4x = 9
d. 4x + 9 = 50
e. y = 9x + 50
f. y = 9x