\(\dfrac{3-5x}{-4}\le0\)
\(\Leftrightarrow\left(-4\right).\dfrac{3-5x}{-4}\ge0.\left(-4\right)\)
\(\Leftrightarrow3-5x\ge0\)
\(\Leftrightarrow3\ge5x\)
\(\Leftrightarrow5x\le3\Leftrightarrow x\le0,6\)
\(\dfrac{3-5x}{-4}\le0\)
\(\Leftrightarrow3-5x\ge0\) ( Vì -4 <0 )
\(\Leftrightarrow3\ge5x\)
\(\Leftrightarrow5x\le3\)
\(\Leftrightarrow x\le\dfrac{3}{5}\)