Melody

Sat 25/10/14

1) Calculus - rates - I like these but I got really frustrated because there are only 100cm in a metre.  Doh!  

Thanks Chimp Ayumu, LancelotLink, Chris and Alan (and even I eventually got it right)      

Hi Rosala,

Well if it is not a private matter then you probably should ask me to pass your message on.

OR

You can send a message to admin if you want.

And there is an email address under the 'about' tab at the top of the page. 

I am not sure if he will actually get your message though.

Ok you got me Chris.

Now yours really is more fun.

Look what you have done now.       

Did you know that greif tears have got more protein in them than 'onion' tears and one possible reason is that the protein acts like a sort of glue making the tears form perfect droplets and it also slows them rolling down the face.  Hence the protein increases the visual stimuli of tears.   People are hard wired to respond to tears.  So cave people who cried when they were greiving or in pain were likely to be looked after better and were hence more likely to survive then those that could not produce the tears.

It is just a theory. But I like it.  :)

How are my triple tears affecting you Chris.      

Is this what you mean?

$$4\times \left(\frac{3}{4}\right)^3\times \left(\frac{4}{7}\right
)^2\\$$

I have not done the rest but I will give you hints on where I would start.

2) Try expanding and simplifying first and see if that helps

3) Think of it as  ((y^3)^2-1^2) and go from there.

4) standard factorising

5) It is a difference of 2 squares.

you have a go and get back with what you have found/done.  We can take it from there.  :)

$$\\1)\\\\
8n(2n-1)-5(2n-1)(2n-1)\\
=8n(2n-1)+(-10n+5)(2n-1)\\
=(8n-10n+5)(2n-1)\\
=(-2n+5)(2n-1)\\
=(5-2n)(2n-1)\\$$

Have you tried to do these for yourself?

Are you asking us to do it fast?

Do you know how rude that sounds?

28x²+24xy-27y²

I am looking for 2 numbers that add to 24 and multiply to  -28*27

a+b=24   and ab=-28*27

solving this simultaneously I get a and b are  -18 and 42

$$\\28x^2-18xy+42xy-27y^2\\
=2x(14x-9y)+3y(14x-9y)\\
=(2x+3y)(14x-9y)$$

B  

$$\\28x^2+24xy-27y^2-6x-9y\\
=(2x+3y)(14x-9y)-3(2x+3y)\\
=(2x+3y)(14x-9y-3)$$ 

There you go - just as well everyone wasn't in a narky mood.    

N=16 degrees 

there you go.

2 good approaches - 2 good answers.

CPhill's is a little more 'mathematical' than mine but mine's more fun.