[tex]\displaystyle\bf\\\frac{3}{8} x\leq -\frac{3}{4}\\\\\\x\leq -\frac{3}{4} :\frac{3}{8} \\\\\\x\leq -\frac{3}{4} \cdot \frac{8}{3} \\\\\\x\leq -2\\\\\\Otvet \ : \ x\in\Big(-\infty \ ; \ -2\Big][/tex]