BarandaMan wrote:

I get it to equal 6 funnily enough, not 3 xD!

I didn't have the WHOLE expression over alpha (which =2), I left that out by mistake, sorry! So it does in fact equal 3! Yay!

Ok,

my other solution for e, which I hope is what you got, is:

e= ((alpha*A)  + g* - ((b* + gammaA - b)/gamma)) / alpha (the whole thing over alpha)

Actually I didn't (post 28) .  But that doesn't mean you are wrong (what did the spreadsheet give you?).

Why so many answers to this? :

an expression for 'e', without using 'e','r', or 'a*'....

Well there is a good reason why this happened.

There are 4 equations and 12 variables.  For the first part you were asked to get one equation with 3 variables forbidden.  It worked like this:

4 equations and 12 variables ... eliminate e gives

3 equations and 11 variables ... eliminate r gives

2 equations and 10 variables ... eliminate a* gives

1 equation and 9 variables.

So we have lost the three variables exactly as required.  There's only one answer. (with maybe a bit of re-arranging)

For part two you are asked for one equation with two variables forbidden ( 'e' doesn't count because that's the one we are trying to make)

4 equations and 12 variables ... eliminate 'r'

3 equations and 11 variables ... eliminate a*

2 equations and 10 variables.

We've eliminated the forbidden variables but still have two equations.  You can still eliminate a variable if you want and get a correct equation.  But which one to eliminate?  There's lots of choices so lots of answers.  Your teacher is going to have lots of work checking each different answer to see if it works.    Unless the question is worded in such a way that it steers you towards one answer rather than another.

Bob

Last edited by bob bundy (2013-03-11 07:07:34)

Happy to have been of help.  As for the many answers, we'll just have to see.

Bob