Answer:
Given formula is :
S = 
We have p = 8500
r = 12.7% or 0.127
(a) when t = 18 months or
years
S = 
=
=
= 1.20985
S = $10283.73
(b) Investment doubles means S = 


=> 
Taking log on both sides

We get t = 5.45 years
Answer:
4x^2 -25
Step-by-step explanation:
(2x + 5)(2x - 5)
FOIL
first: 2x*2x = 4x^2
outer : 2x*-5 = -10x
inner : 5*2x = 10x
last: -5*5 = -25
Add them together
4x^2 -10x +10x -25
Combine terms
4x^2 -25