Question 896594
Well here t should be a variable. Lets think this starts from year 2000 which makes t = 0. And find the value of it in 2000. Think it's then value is C.

V = C - 135t

In 2013 t=13

2700 = C - 135*13

2700 + 135*13 = C (it's value in 2000)

4455 $ = C

So lets make equation. t = {Z+}

V = 4455 - 135t

V = 135*(33-x)