2\5а-1,4=-1\2а-3,2 и ещё 1 (у-3):4=(5-2у):(-9)

$1.) \frac{2}{5}\cdot a - 1,4 = \frac{1}{2}\cdot a - 3,2\\\\ \frac{2a}{5}-\frac{a}{2}=-3,2+1,4\\\\ a (\frac{2}{5}-\frac{1}{2})=-1,8\\\\ a(\frac{4}{10}-\frac{5}{10})=-1,8\\\\ a\cdot (-0,1) = -1,8\\\\ a = \frac{-1,8}{-0,1}\\\\ a = 18\\\\$

$2.) \frac{y-3}{4}=\frac{5-2y}{-9}\\\\ \frac{9(y-3)}{36}=\frac{-4(5-2y)}{36}\\\\ 9(y-3)=-4(5-2y)\\\\ 9y-27=-20+8y\\\\ 9y-8y=-20+27\\\\ y=7$