$\displaystyle \left(-\infty,- \frac{3}{4} \right)$\displaystyle \left(-\infty,- \frac{3}{4} \right)

$\displaystyle \left(- \frac{3}{4},+\infty \right)$\displaystyle \left(- \frac{3}{4},+\infty \right)

$\displaystyle \left(-\infty,- \frac{3}{16} \right)$ \displaystyle \left(-\infty,- \frac{3}{16} \right)

$\displaystyle \left(- \frac{3}{16},+\infty\right)$\displaystyle \left(- \frac{3}{16},+\infty\right)