ElectricPavlov

Oopps...I didn't read the entire question ...

  the three math books together can be arranged in   6 ways    ( 3!   or  3 P3) 

   then they act as one object of 5 objects     5 P 5 = 120 ways to arrange the books     ( 5!) 

Then  6 x 120 =   720 ways    

b + (b + 100) = 200      Given 

2b = 100

b = 50   cents 

7 P 7 =   7!  = 5040  ways 

     or

7 choices for first book 

6 choices for second book 

5 choices for third book 

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1 choice  for last book                   7x6x5x4x3x2x1 - 7! = 5040 ways 

(x-1) = 0 produces a root of x =1 

(x+1) = 0 produces a root of -1 

  multiply them together :

(x-1)(x+1) =0

x^2  +  (0) x  - 1  = 0       or simply   x^2 -1 = 0 

Where the graphs intersect, they are equal :

x^3 + x^2 -3x + 5   =  x^3 + 2x^2

x^2 -3x + 5 = 2x^2 

0 =  x^2 +3x -5

   Now use Quadratic Formula with   a = 1  b = 3  and c = -5    to find x = 1.193    and -4.193

   Now use these values of 'x' in either of the equations to find the corresponding 'y' coordinates.  

Start with 1011  then add 21 sequentially until you reach 1998 to find   48 numbers 

100 ft^2 / ( 10 mem * 10 min) =   1 ft^2 /( mem_ min) 

100 ft^2 / ((1 ft^2 /mem_ min) * 15 mem ) = 6 2/3 min