CPhill

C(12, 3)  = 220

1 acre = 43,560 sq ft   ....  so......

1,000,000 / 43, 560 =  about  22.96 acres

I think this must be :

81x^2 + kx + 25    if so....we can take the square roots of 81 and 25   =  9 and 5  ...multiply them together = 45  ..... and double this  = 90   and this is "k'  .....

Note

81x^2 + 90x + 25 =

(9x + 5) (9x + 5) =

81x^2 + 45x + 45x + 25  =

81x^2 + 90x + 25

I'm going to assume that the pyramid has a square base equal to that of the cube. If so....the cube will be a prism that has the same base and height as the pyramid. And the volume of prism is three times that of its associated pyramid.....so.......the cube has a voume of 54 cu ft

Mellie.....others on this site  (Melody, for instance) are better at these than I am.....but I'll venture an answer

I see all the white b***s as being indistiguishable  from each other....and the same with the black b***s

So.....this amounts to the same thing as the number of identifiable "words" we could form with, say, 4 e's and 4 h's'

And this is given by    8!  / (4! * 4!)  =  70

There are only 2 ways to draw alternate colors  .... BWBWBW.......etc.    or   WBWBWB......etc.

So.....the probability of alternating colors on the draws is just  2 / 70   or 1 / 35

If this isn't correct......maybe wait until Melody comes on later.....

3cos (-300)+sin180    ....  the sin of 180 = 0 ....  and  cos (-300) = cos (60) = 1/2

So....

3  x 1/2   =  3/2   = 1.5

There is no real number solution for this.....

The quantity under the square root has to be > 0.....and as large as it could be is when x = 0

But, this gives us the square root of 1  which equals 1......and that can never equal 1.046....!!!

2a/3=8   multiply both sides by 3

2a = 24   divide both sides by 2

a = 12