The second one that you did
Answer:
a. 
Step-by-step explanation:
The given equation is;

To solve by the x-intercept method we need to graph the corresponding function using a graphing calculator or software.
The corresponding function is

The solution to
is where the graph touches the x-axis.
We can see from the graph that; the x-intercepts are;
(-1,0),(3,0) and (6,0).
Therefore the real solutions are:

Answer:
The answer is "26179.4".
Step-by-step explanation:
Assume year 2000 as t, that is t =0.
Formula:

Where,

for doubling time,


Given value:



when year is 2000, t=0 so, year is 2100 year as t = 100.
