a,\(\Leftrightarrow\frac{x}{0,2}=\frac{x}{0,8}\Leftrightarrow0,8x=0,2x\Leftrightarrow0,6x=0\Leftrightarrow x=0\)
b,\(\Leftrightarrow\frac{x+11}{14-x}=\frac{2}{3}\)
\(\Leftrightarrow3\left(x+11\right)=2\left(14-x\right)\)
\(\Leftrightarrow3x+33=28-2x\)
\(\Leftrightarrow3x+2x=28-33\)
\(\Leftrightarrow5x=-5\Leftrightarrow x=-1\)