$$.670=\frac{x}{(1-x)(2-x)}.$$
It is unclear whether .670=x/(1-x)*(2-x) is supposed to mean $0.670 = \frac{x}{(1-x)(2-x)}$ or $0.670 = \frac{x}{(1-x)}(2-x)$.
In either case, Yuval Filmus's advice of multiplying by the denominator works. In the first you get $0.670(1-x)(2-x) = x$ and you can expand and move all the terms to the left hand side. In the second you get $0.670(1-x) = x(2-x)$ and you can again expand and move all the terms to the left hand side.