I can solve three equations for x like this

restart:
x := y/p:
z := x*a+y*(1-b):
x := 100*z/(p*r+r);

                            /y a            \
                        100 |--- + y (1 - b)|
                            \ p             /
                   x := ---------------------
                              p r + r      

However, I dont like the fact that x is a function of y. I just want x to be a function of a, b, p and r. So I try to expreses the equations as follows:

restart;
y := p*x;
x := 100*z/(p*r+r);
z := x*a+y*(1-b);
solve(z, x);

Error, recursive assignment
Warning, solving for expressions other than names or functions is not recommended.

Any idea how I can get an equation for x that only depend on a, b, p and r? 
 

Is there a way to solve these equations x+y = 373320 and z = (x+y) / 0.44 - y -  y* (1 - 0.99) for x,y,z in Maple or excel?

Even if we set y = 37320 - x 

and plug that in we get z= 37320/0.44 - (37320-x) - (37320 - x) * (1-0.99) there are still two unknown z and x

Maybe some optimization?  Thanx for any input

Lets say you a country where the official government debt (not adjusted for who owns the debt) is 30% of GDP. The official government debt consist of 50% government bonds and the central banks owns 40% of these government bonds. Since the government finance the centralbank we have to adjust the official government debt and remove the 40% of the government bonds that the centralbank own to get the real government debt expresed as % of GDP. In my initial calculation I simply did like this:

Real government debt expressed as % of GDP = 0.3*(1-0.4) =18%

However, that such number does not take into consideration that the official government debt is only made up of 50% government bonds. I tried to play around with different types of equations but I found none that makes any logical sense and provides me with a reasonable number. I would expect the real government debt to around 23% of GDP. This might be a simple question but I must admit I am stuck and I am not making any progress.  Any help would be appreciated.

I am trying to model a disease. The equation is as follows:

S*X - f(X,S,Sp) = 100

I have data for S, I have data for X and I have data for f(X,S,Sp) however I want to find an equation for f(X,S,Sp) that has the best fit with the data because I need to use it later on in my calculation. If anyone is intrested S is the sensitivity of the blood test, Sp is the specificity of the blood test. This means that X*(1-Sp) is the number of false positives.

I currently dont have access to Maple hence I am doing all my modeling in excel 2016. So I am severly limited because excel is useless at algebra.

Maple.xlsx

I have not been using Maple for the last couple of years because I have Maple installed on my big and heavy laptop. Such laptop forces me to sit at a desk when I work which I dont like. This has resulted in that I have only (for the most part) used my ipad for the last couple of years hence dropping my laptop and Maple. The problem with such approach has been that is more difficult to write scientific papers because you cant run a full version of word on the ipad hence you cant use a citation manager. There does not exist an app on the ipad that offer one. This leads to a lot of extra work!

I have therefore now bought a Microsoft Surface Pro 4 which is a tablet (like the ipad) but its a not a "toy" tablet like the ipad or android tablets because it has Windows 10 Pro (64-bit) which means that you can run full versions of pc software like word 2016 and Maple. The version of Surface Pro 4 I bought has an Intel Core m3-6Y30 processor with 2 cores, 4GB RAM, 128 GB of storage, no fan and a processor base frequency of 0.9 GHz. The m3-6Y30 processor has something called dynamic frequency scaling which means (as I understand it) that the processor can go up to 2.2 GHz when it is under heavy load. Since Maple recommend that you have a system with a cpu with at least 1 GHz to run Maple 2016 I am not anticipating any problems here.

http://www.maplesoft.com/products/system_requirements.aspx

However, I am not completly sure if maplesoft means that the base frequency needs to be 1 Ghz or not? Since my tablet has not been delivered yet I cant comment on how Maple runs on it but as I said I am not anticipating any problems.

Now to my question: When will Maple 2017 come out? Since it is already 2017 I dont want to buy an old version of Maple now that I want to update my Maple software.