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If I have

$ 60 = 40/X + X $

How do I remove $40$ and find $X$?

As I understand it, I have to multiply both sides by $X$. But if I do that then I'm left with

$ \begin{eqnarray*} &60X = 40 + X &\Rightarrow \\ &60X - X = 40 &\Rightarrow \\ &X - X = 40 / 60 &\Rightarrow \\ & 1 = 2/3 & \end{eqnarray*} $

And I think I ended at the wrong spot...

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    @Aedon, yes -- you do it for each _term_, whether or not they contain variables. It's not a special magical rule, it's just the ordinary $a(b+c)=ab+ac$ applied with $a=x$, $b=\frac{40}{x}$ and $c=x$.2011-10-17

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You know $X\ne 0$ so you can multiply by it. That will leave you a quadratic equation for $X$.

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    Ok I see now, thank for the help :)2011-10-17