An investment of $8000 in a certain certificate of deposit (cd) doubles in value every 7 years. the function that models the growth of this investment is f(x)=8000•2^x, where x is the number of doubling periods. if the investor does not withdraw any money from this cd, how much money will be available for withdrawal after 28 years?

the available amount after 28 years is $128000

Step-by-step explanation:

The initial value of the investment is

$8000. The value doubles in every 7 years.

The function that models the growth of this investment is f(x)=8000•2^x

where

x represents the number of doubling periods.

To determine the amount of money that will be available for withdrawal after 28 years, we would determine the number of doubling periods first. Therefore,

x = 28/7 = 4

Therefore, the available amount after 28 years would be

f(x)=8000•2^4 = 8000×16 = $128000

$128,000.

Step-by-step explanation:

28 years is 4 doubling periods ( 4 * 7).

So the amount of money after 28 years

= 8000* 2^4

= $128,000.

solution:

the given function is ,

      =

the three roots of this quadratic function is , 0 ,8 and 10.all the roots are real and rational.

if a quadratic equation is of the form ,

sum of the roots = a + b +c= 0+8+10=18=  

product of roots taken two at a time = a b + b c+ c a = 0+80+0=80 =  

product of roots = a b c = 0=  

there are 11 doors in a hall starting from 0 to 11.the entry in the hall is permitted through gate number 0 and exit is allowed through only gate number 8 and 10.so, three roots(0,8,10) of quadratic function is given by entry and exit route of this hall.