CPhill

The sum, S_n  .....  is given by :

S_n  = .10 [ ( 1 - (3)^14) / ( 1 - 3)  ]   =  $239,148.40

TR.....I think you mis-copied the problem....it was

x + 2y   = 8

x -  2y   = 4

And there definitely is a solution for this....!!!

(8xy)(-5y)  =

(8 * -5)  * (x) * ( y * y)  =

-40 xy²

Spawn made a slight typo on this one......but....he was on the right track.....

12 * 8 * .25  = 24 yds^3

And the total cost =

$55 * 24  = $1320

[ I'll still give you 5 pts, Spawn......LOL!!!]

(1/3) / (2/10)  =

(1/3) * (10 / 2)  =

10 / 6  =   5 / 3

5/3 rds more 1/3rds  than 2/10ths

-4 = 3x -16       add 16 to both sides

12 = 3x      divide both sides by 3

4  = x

5m+3n=14     (1)

2m+n=6  →    n  = 6 - 2m    (2)

Putting   (2)  into (1), we have

5m + 3 [ 6 - 2m ]   = 14     simplify

5m + 18 - 6m  =  14

-1m + 18 = 14       subtract 18 from both sides

-1m  = - 4          divide both sides by -1

m = 4

And

n = 6 - 2(4)   =    6  - 8   =  -2

So  (m, n)  = ( 4 , -2)

Enquired , it's sort of become my "trademark" .......LOL!!!!

See  ????

25000 = 2^x        take the log of both sides

log 25000  = log 2^x      and we can write

log 25000  = x * log 2      divide both sides by log 2

log 25000 / log 2  = x  = about   14.61

10 1/3 x 4 x 8 4/5

10 1/3  =    31/3

8 4/5   =  44/5     ....   so we have

(31/3) * (4/1) * (44/5)  =

5456 /  15   =  about  363.73 units^3