ElectricPavlov

The answer is A

(8+16+24+32+40)/5 = average stamps per day

This is a circle centered at 6,0   with aradius of 8

The line goes right through the center ...and has a slope of -1   

     so it forms a 135^o angle with the x axis

Total area = pi 8^2

    for the 135 degree portion    135/360 * pi * 8² = 75.4  units²

Here  is a picture:

https://www.desmos.com/calculator/kusprk1stg

10 years

original pop 21000   decreases    continuously

21000 e^-kt     when t = 10 years  pop = 20000

20000 = 21000 e^-10k

^{k = .004879}

 2010    t = 30               21000 e^{-.004879 (30)}  = ~~ 18141 population in 2010

That would be a number witha 7 in the same position as the two is in 1273

  x7xx   <========  this seven is 10 times larger than the seven in 1273 because it is

                                                         one postion further to the left

q = # quarters         value  = 25q

d = #dimes              value = 10d

q+ d = 25

25q + 10d = 385      from first equation   d = 25-q    use this in the second equation

25q  + 10(25-q) = 385         now you can solve for  q      then d   = 25-q

25q+250-10q = 385

15q= 135

q = 9   quarters       d = 25 - q = .......

1/2 of the angle at O     arcos (7/12) = 54.31^o

    so O is 108.6 ^o

        the arc you are looking for is   360 - 108.6 = 251.37^o

^{Pi (2*7)  x   251.37/360 = .....}

Go backwards from her result of 7

   multiply by 3  =21

     subtract 2    = 20

        divide by 4  = 5   is the original number....now proceed with the steps in the second half of the question

f(x) = -7        soooo        -7 =  4x-3

                                       -4  = 4x

                                         x = -1

I think you can now do the others ! 

First one

   just put  '2' in to the equation for 'x'

       4(2) - 3 = 5

now put -10 in for x

the last one....put 0 in for x .......