Answer:
b = 2
Step-by-step explanation:
In order to find the value of b, we have to isolate b on one side of equation first
So,

Multiplying 2 with b-1

Adding 2 on both sides

Dividing by 5 on both sides

So the value of b is 2 ..
Answer:
84%
Step-by-step explanation:
84%
63 divided by 75 is 0.84. 0.84 is also 84% so the answer is 84%.
This is a compound interest problem so you cannot use the simple interest formula. Effectively the total amount is being compounded each year by 6%. There is a formula for compound interest but in this simple example you can work this out recursively.
year 1 = 6500
year2 = 6500*1.06 = 6890
year3 = 6890*1.06 = 7303
year4 = 7303*1.06 = 7741..
etc......
year12 = 11604*1.06 = 12338