[tex]\dfrac{km}{3}-2x=4\ \ \ \ |subtract\ \dfrac{km}{3}\ from\ both\ sides\\\\-2x=4-\dfrac{km}{3}\ \ \ \ \ |change\ signs\\\\2x=\dfrac{km}{3}-4\ \ \ \ \ |divide\ both\ sides\ by\ 2\ (multiply\ by\ \frac{1}{2})\\\\\boxed{x=\dfrac{1}{2}\left(\dfrac{km}{3}-4\right)}\ \ \ \ |use\ distributive\ property:a(b-c)=ab-ac\\\\\boxed{x=\dfrac{km}{6}-2}[/tex]
