a. $x+\left ( -\frac{2}{9} \right )=\frac{-7}{12}$
$x=\frac{-7}{12}+\frac{2}{9}$
$x=\frac{-21}{36}+\frac{8}{36}$
$x=\frac{-13}{26}$
b. $(-0,1)-x=\frac{-7}{6}$
$\frac{-1}{10}-x=\frac{-7}{6}$
$x=\frac{-1}{10}+\frac{7}{6}$
$x=\frac{-3}{30}+\frac{35}{30}$
$x=\frac{32}{30}=\frac{16}{15}$
c. $(-0,12).\left ( x-\frac{9}{10} \right )=-1,2$
$\frac{-3}{25}.\left ( x-\frac{9}{10} \right )=\frac{-6}{5}$
$x-\frac{9}{10}=\frac{-6}{5}:\left ( \frac{-3}{25} \right )$
$x-\frac{9}{10}=\frac{-6}{5}.\frac{-25}{3}$
$x-\frac{9}{10}=10$
$x=10+\frac{9}{10}=\frac{109}{10}$
d. $\left ( x-\frac{3}{5} \right ):\frac{-1}{3}=0,4$
$\left ( x-\frac{3}{5} \right )=\frac{2}{5}.\frac{-1}{3}$
$x-\frac{3}{5}=\frac{-2}{15}.\frac{-1}{3}$
$x-\frac{3}{5}=\frac{-2}{15}$
$x=\frac{-2}{15}+\frac{3}{5}$
$x=\frac{7}{15}$