We know that the value of the house doubles each decade.
Then, the value can be written as:
where d is the actual decade, and (d-1) is the previous decade.
If d=0 is the decade of 2015, we have:
We have the explicit formula of the value as:
Now we can use this formula to calculate the value of the house for any decade.
When d=-1, the value is:
When d=-2, the value is:
Answer:
1. V(d) = 400,000 * 2^d
2. V(-1) = 200,000
3. V(-3) = 100,000