Answer:
a) 
b) 6.84 million
c) 2028.52
d) 47 years
Step-by-step explanation:
a)Here we know standard exponential growth rate is

In this put t=0 and a(t)=6.27 million
thus we get a = 6.27 million
now 
this is equal to(in 2012)=
b)Put t = 6
we get

=6.84 million
c) 
take log both sides
we get 16.52 years
d) 
take log both sides we get 47 years to get double the current population.
I hate rounding.
Let's call the diagonal x. It's the hypotenuse of the right triangle whose legs are the rectangle sides.
According to the problem we have a length x-4 and a width x-5 and an area
82 = (x-4)(x-5)
82 = x^2 - 9x + 20
0 = x^2 - 9x - 62
That one doesn't seem to factor so we go to the quadratic formula

Only the positive value makes any sense for this problem, so we conclude

That's the exact answer. Did I mention I hate rounding? That's about
x = 13.6 meters
Answer: 13.6
----------
It's not clear to me this problem is consistent. By the Pythagorean Theorem the diagonal satisfies

which works out to

That's not consistent with the first answer; this problem really has no solution. Tell your teacher to get better material.
If it is 1/(3x+2), 3x+2≠0 =>x≠-2/3, the domain is all real number except -2/3
if it is 1/(3x)+2, 3x≠0, x≠0, the domain is all real number except 0
It is hard to tell from your equation what the demonstrator is.
Answer:
0.078
Step-by-step explanation:
Margin of error = z√(p(1-p)/n)
Given
p-hat = 0.43
n = 270
z at 99% confidence interval = 2.576
Substitute
MOE = 2.576√0.43(1-0.43)/270
MOE = 2.576√0.43*0.57/270
MOE = 2.576√0.2451/270
MOE = 2.576*0.030129
MOE = 0.078
Hence the margin og error is 0.078