Answer: $7787.99
Step-by-step explanation:
We know that the formula to find the periodic payment on an annuity is given by :-
, where PV is the present value , r is the rate of interest ( in decimal ) and n is the number of payments.
Given : Present value : $36000
Rate of interest = 8%=0.08
Time period = 6 years
Then , the periodic payment will be :-

Hence, the payment size is $7787.99.
Answer: -8 and -4
This is something you do through trial and error. Making a list or a table like shown below might help.
The answer is 12.
Steps
If that number is x
(3+x)/(8+x)=3/4
"Cross multply"
4(3+x)=3(8+x)
12+4x=24+3x
x=12
To check: add 12 to 3 and 8. 3+12=15 and 8+12=20. 15/20=3/4