а) 2 - x > x + 18
-x - x > 18 - 2
-2x > 16
x < - 8
-\\\\\\\\\\\\\\o--------->
-8
x∈ (-∞; -8)
Ответ: (-∞; -8)
б) 
\frac{3x+15}{2}" alt="\frac{x-1}{2}-3x>\frac{3x+15}{2}" align="absmiddle" class="latex-formula">
\frac{3x+15}{2} \\ -5x-1>3x+15\\ -5x-3x>15+1\\ -8x>16\\ x<-2" alt="\frac{x-1-6x}{2} >\frac{3x+15}{2} \\ -5x-1>3x+15\\ -5x-3x>15+1\\ -8x>16\\ x<-2" align="absmiddle" class="latex-formula">
-\\\\\\\\\\\\\\o--------->
-2
x∈ (-∞; -2)
Ответ: (-∞; -2)