CPhill

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      Old Value

[6000 - 5000]

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    5000 

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1

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 5

3x^2 + 4x  - 8  = 0

Use the quad formula  with   a  = 3   b = 4  and c  =  -8

So  we have that

                -4 ±√ [ 4^2 - (4 * 3 *  -8) ]            -4 ±√[16 + 96]            -4 ± 4√ [ 1 + 6]

 x =          _____________________   =    _____________  =    ____________ =

                             2 * 3                                        6                             6

- 2 ± 2√7

________  =    "C"

      3

That icon was DS.....yep....I think he "borrowed" my icon for a bit....LOL!!!!

You were definitely the "red dino,"  Melody.......!!!!

So many people who have come and gone......good memories  ( of most of them )

Given f(x)=5x+2 and g(x)=3x^2-4x, evaluate f(f(1))-g(g(2)).

f(1)  =  5(1) + 2  = 7

So ....   f (f(1))  = f(7)   = 5(7) + 2  = 37

g(2)  =   3(2)^2 - 4(2)  =  4

So  ....    g(g(2) )  =  g(4)  =  3(4)^2 - 4(4)  =  32

So

f(f(1))  - g (g (2) )  =

37  -  32   =

5

2 * ( 2*pi * r)   =  pi * r^2       divide through by pi

2 * 2 * r  = r^2

4 r   =  r^2       rearrange as

r^2  - 4r   =  0       factor

r ( r - 4) = 0

Set each factor to 0  and solve for r and we get that

r  =  0   inches    (reject)

r  = 4 inches       (accept)

AHHHHHH!!!!

How could I forget  ???

This one was due to   Zegroes  ( and old member, sadly gone)  calling Melody and I "dinosaurs".....

I think she had another "dino" pic, too.....

I remember this one.....I thought she also had another when I first joined the site, but I can't remember what it was ........(maybe I'm dreaming....LOL!!! )

THX, guest  !!

Corrected  !!!!

Don't worry, CU......as good as you are in math, the trig "secrets"  will come easily to you....!!!!

Here's another  (less neat ) solution

We can guess that   the answer   might be    88 _ _

Note that   8901  is a multiple of 9   because the sum of its digits is divisible by 9

We need to subtract  some odd multiple of 9 from this to produce an integer with all even digits

The possibilities are 9, 27, 45, 63, 81

81  is the one we need

So

8901  - 81  =

8820  !!!   (as the guest found)