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# how is the algebra done watch

1. self-explanatory, how do you achieve the final results (equations 3.14 and 3.25)? I could not figure it out.

Thanks
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2. If you want to do it the way they expect, take the expression they suggest for and substitute into the 2nd equation to get . Then it's fairly straightforward manipulation to finish (I would start by multiplying the equation by c_2).

I'd say it's cleaner here to multiply the first equation in 3.13 by and the 2nd by . Then both equations have a term, so by subtracting one from the other, you eliminate P_2 and can find P_1.

You haven't posted enough to comment about (3.25); none of the variables there are mentioned anywhere else in what you post.
3. (Original post by Logolept)
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4. (Original post by DFranklin)
If you want to do it the way they expect, take the expression they suggest for and substitute into the 2nd equation to get . Then it's fairly straightforward manipulation to finish (I would start by multiplying the equation by c_2).

I'd say it's cleaner here to multiply the first equation in 3.13 by and the 2nd by . Then both equations have a term, so by subtracting one from the other, you eliminate P_2 and can find P_1.

You haven't posted enough to comment about (3.25); none of the variables there are mentioned anywhere else in what you post.
I'm sorry I was not clear, it is the algebraic manipulation in both questions that confuses me. The substitution and stuff I get.
5. (Original post by Logolept)
I'm sorry I was not clear, it is the algebraic manipulation in both questions that confuses me. The substitution and stuff I get.
Post your attempt. No-one is going to do it for you. (I note also that I posted two methods, and for the second one I posted the algebra is very easy. Bluntly at this point I'm unconvinced you're putting in enough effort of your own...)

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