2/9*(1,8-1 1/2а)-1 1/6(1,2-2/7а) упростить подробно срочно посиб

$\frac{2}{9}*(1,8-1\frac{1}{2}a)-1\frac{1}{6}(1,2-\frac{2}{7}a)= \frac{2}{9}*(\frac{9}{5}-\frac{3}{2}a)-\frac{7}{6}(\frac{6}{5}-\frac{2}{7}a)=\\\\=\frac{9*2}{5*9}-\frac{3*2}{2*9}a-\frac{6*7}{5*6}+\frac{2*7}{7*6}a=\frac{2}{5}-\frac{3}{9}a-\frac{7}{5}+\frac{2}{6}a=\frac{2}{5}-\frac{1}{3}a-\frac{7}{5}+\frac{1}{3}a=\\\\=\frac{2}{5}-\frac{7}{5}=\frac{2-7}{5}=\frac{-5}{5}=-1$
Ответ -1