From Förberedande kurs i matematik 1

Because there is an x on both the left- and right-hand sides, the first step is to subtract x/3 from both sides,

\displaystyle \tfrac{1}{3}x-1-\tfrac{1}{3}x=x-\tfrac{1}{3}x

so as to collect x on the right-hand side

\displaystyle -1=\tfrac{2}{3}x\,\textrm{.}

Then, multiply both sides by 3/2,

\displaystyle \tfrac{3}{2}\cdot (-1) = \tfrac{3}{2}\cdot\tfrac{2}{3}x\,,

so that 2/3 can be eliminated on the right-hand side to give us

\displaystyle -\tfrac{3}{2}=x\,\textrm{.}