Answer:
The investment required is: $5687
Step-by-step explanation:
Future Amount A= $7000
Rate r = 6% =0.06
Time t = 4
Compounded Weekly = n= 52
We need to find Principal Amount P
The formula used is: 
Putting values and finding P

So, The investment required is: $5687
0 x is 132 and A, B, and C are 62