Answer:
-b years from now
Step-by-step explanation:
The age of Adam = d
The age of Brandon = b
The number of years Brandon is older than Adam = b
Therefore;
b = d + b
∴ d = 0
Therefore, Brandon will be twice as old as Adam is now when Brandon is 2 × 0 = 0 years
The number of years before Brandon will be twice as old as Adam is now = 0 - b = -b years from now