This is a formula for interest. it is in the tables book. the formula is F=P(1+i)^t
p=the starting amount
i the rate of interest, converted from % to decimals. e.g 5%=0.05
t= the amount of time.
this question asks you to work backwards after giving you some information. fill the numbers into the formula. the first number in the bracket needs to be1 and so the question is dividing the bracket by 5088.50 to get it to equal to 1.
Hope this helps!:)

Thanks for that
I understand the formula and the rest of it.
What is getting me is the second line in the attached. The algebra side of it? Where did the 1 come from?
Is it some form of factorising?
Thanks.

clark13— 07/05/16