# Homework Help: Horid algebra

1. Jul 29, 2008

### franky2727

ive got (y-1/y+2)=Ke3/4x4where K=+ or- e3c

and im trying to get to y=(2Ke3/4x4)/(1-Ke3/4x4)

but i keep getting y= (-3+Ke3/4x4)/(Ke3/4x4) can someone please have a go at this to see if its me thats wrong or the answer sheet and if its me which it usualy is can you please write your working step by step? thanks

2. Jul 29, 2008

### 3029298

We have:

$$\frac{y-1}{y+2}=KL$$

In which $$K=\pm e^{3c}$$ and $$L=e^{\frac{3}{4}x^4}$$

We now work this out:

$$y-1=yKL+2KL$$

$$y=yKL+2KL+1$$

$$y-yKL=2KL+1$$

$$y(1-KL)=2KL+1$$

$$y=\frac{2KL+1}{1-KL}$$

This does not correspond to the solution you want to get, but in my opinion this is the correct one, maybe you have not given the correct question?

3. Jul 29, 2008

### franky2727

ye thats right sorry i forgot to put the +1 on the end and that way is about 50^2 times simpler than the way i was trying to do it thanks!

4. Jul 29, 2008

### 3029298

no problem sometimes the math becomes easier if you just replace some nasty crap by a single parameter