Melody

whats 2ab plus -9b

They are unlike terms so you cannot put them together with plus or minus

2ab + - 9b

Minus numbers or terms are 'cold'

so here you are adding cold so the room will gett colder.   So  + - is replaced with a -

=2ab - 9b

Oh yea, I didn't even notice LOL

Well the asker got both questions answered:)

Thanks TayJay :)

What if there are 2 middle ones TayJay?

The derivative is the gradient of the tangent to the curve at any given point.

if the curve is a line as it is in f(x)=2x-2 then the gradient stays the same all the time.

The gradient of this line is 2.  Therefore the derivative is 2.  

You are welcome :)

I am sorry Rosala, I shall go back and recify the problem.    

(I'll give you some points to to amke up for my negligence. :))

The number of ways 10 people can stand in a queue is 10!

now lets treat the 3 fiends as siamese triplets.  that means there are the triplets and 7 other people in the queue.  that is 8 altogether.

that would be 8! permuations BUT  the 'triplets' can be joined in 3! orders. 

So the number of ways that the friends can be together is    8!3!

so the probability that the friends are in the queue together is      $$\frac{8!3!}{10!}=\frac{2*3}{9*10}=\frac{1*1}{3*5}=\frac{1}{15}$$

@@ End of Day Wrap   Wed 11 /2/15 Sydney, Australia Time 12:55 am  (Really Thurs morn)  ♪ ♫

Good evening/morning 

Well I have been busy and I know CPhill was equally busy earlier in the day.  Just as well we have so many helpers.  Today these were  Alan, TakahiroMaeda, Heureka, CPhill, Tetration, Wildhorse, JuiceBox, GenericUserNameHere, Saseflower, geno3141, BrittanyJ, Thatguy0123, mathematician, HappyBJ, TBoy1, Sobewo and of course our ever helpful Rosala (who I temporarily forgot, sorry Rosala).  Thanks all, you are all much appreciated. 

Interest posts:

Thurs 12/2/15