Answer:
y = 100 + 25 x
Step-by-step explanation:
We need to write an equation to calculate the cost y based on the number of months x, so we'll start as:
y = ...
The sign up fee of $100 is payed only once at the beginning, it does not depend on the number of months, so
y = $100 ...
Then the month payment $25, must be added. The month payment will be multiplied to the number of months (x):
y = $100 + $25 x
For example after two months (x = 2) the cost payed will be $100 plus two month payments ($25*2). So y (2 months) = $100 + $25*2 = $150
