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...