$a)$

$2x+7\le 3\mid -7$

$2x\le -4\mid :2$

$x\le -2$

 

$b)$

$\frac{2}{5}x-3>1\mid +3$

$\frac{2}{5}x>4\mid :2$

$\frac{1}{5}x>2\mid \cdot 5$

$x>10$

 

 

 

$c)$

$2x-4<\frac{1}{2}x-1\mid \cdot 2$

$4x-8<x-2\mid -x$

$3x-8<-2\mid +8$

$3x<6\mid :3$

$x<2$

 

 

$d)$

$\frac{1}{4}-x\ge 1-6x\mid +6x$

$\frac{1}{4}+5x\ge 1\mid -\frac{1}{4}$

$5x\ge \frac{3}{4}\mid \cdot \frac{1}{5}$

$x\ge \frac{3}{20}$