Which point has the coordinates of -2.5 5.5

It's the point that's 2.5 units to the left of the y-axis and 5.5 units above the x-axis.  (right there on the picture of the graph that you're hiding from us)

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.

the five characteristics of adolescence are biological growth and development, and undefined status, increased decision making, increased pressure and the search of self.