ElectricPavlov

j = c/k       where c is proportionality constant

42 = c / 56      shows c = 2352

Now when k = 98:

j = 2352/98 = .........

Area =   side x side = 425

                side^2 = 425

                 side = sqrt 425

Perimeter = side + side + side + side

                =  4 * sqrt (425)                         You can simplify it from here .....

1861 = 1000 (1+x)³

1861/1000   = (1+x)³   take cube root of both sides

1.23 = 1+x

x = .23 = 23 %

1/3)⁴  =  1⁴  / 3⁴     =  1/ 81

Cedric in 15 years     12000 (1.05)¹⁵  = $ .........

Daniel                        12000 + 12000(.09)(15) = $........

a(2)^r = 1       2^r = 1/a 

a(128)^r = 5     a(2⁷)^r = 5

                       a (1/a)⁷ =5

                          1/a⁶ = 5

                           1/5 = a⁶

                                  a = .76472449              .764724491 * (2^r) = 1      r = .38699

Assuming all of the books are distinguisible

6 ways to have math on each end

   then there is 7 books left     7 P 7 = 5040  ways to arrange the 7 books

5040 x 6 = 30 240 ways  (I think)

x³ * x⁵   + (x³)² =

x⁸   + x⁶     

.75 gallons per hour ?   REALLY?

anyway     gallons left after 't' hours        gallons_left  =  11 - .75 t

    after 4 hours    11 - .75(4) = ....... gallons left

10000 e^.045(10)   = 15683.12      they will not make it to double 10 000 in 10 years

                              ...they need more time or a higher interest rate to double thier initial investment