You are buying a new laptop, and will pay it off in parts. You have found two shops which sell the model of laptop that

[answerhappygod]

You are buying a new laptop, and will pay it off in parts. You
have found two shops which sell the model of laptop that you
would like to buy, and they offer two different payment plans.
Shop A offers you the laptop for an initial payment of 700 euros
and after that a payment of 40 euros for 24 months.
Shop B offers you the laptop for an initial payment of 300 euros
and after that a payment of 60 euros for 24 months.
Below are some questions based on this information:
(a) Give a linear function representing the amount that
you have paid Shop A after an amount of time, and do the same for
Shop B.
(b) Which shop gives you the cheaper product after 24
months?
(c) At which point will you have paid the same amount of
money to each shop? (If this point of time exists).