From Förberedande kurs i matematik 1

Because there is an \displaystyle x on both the left- and right-hand sides,

the first step is to subtract \displaystyle {x}/{3}\; from both sides,

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

so as to collect \displaystyle x on the right-hand side

\displaystyle -1=\frac{2}{3}x.

Then, multiply both sides by \displaystyle {3}/{2}\;,

\displaystyle \frac{3}{2}\centerdot \left( -1 \right)=\frac{3}{2}\centerdot \frac{2}{3}x

so that \displaystyle {2}/{3}\; can be eliminated on the right-hand side to give us

\displaystyle -\frac{3}{2}=x