Tom buys a new phone service. it costs $20 to install, and then costs $15 a month. write an equation to show the cost of the phone (y) for any number of months (x).
a.
y=15x+20
b.
y=20x+15
c.
y=20x-15
d.
15x+20y=35

There are several information's of immense importance already given. Based on those information's the answer can be easily deduced. Let us now focus on the problem in hand.

Number of months = x
Installation charge = $20
Charge per month = $15
Then
y = 15x + 20

From the above deduction, we can conclude that the correct option among all the options given is option "A".