$\displaystyle \left(-\infty, \frac{2}{3} \right]$\displaystyle \left(-\infty, \frac{2}{3} \right]

$\displaystyle \left(-\infty- \frac{2}{3} \right]$\displaystyle \left(-\infty- \frac{2}{3} \right]

$\displaystyle \left[ \frac{2}{3},\infty \right)$\displaystyle \left[ \frac{2}{3},\infty \right)

$\displaystyle \left[- \frac{2}{3},\infty \right)$\displaystyle \left[- \frac{2}{3},\infty \right)