I am very confused. So I have to solve this inequality. The result is $13/24$.
But if I try to solve it myself, I get $17/24$. Because:
$\sqrt{\left(\frac{-5}{24}\right)^2 + \frac{1}{4}} = \frac{5}{24} + \frac{1}{2} = \frac{5}{24} + \frac{12}{24} = \frac{17}{24}.$
The right solution should be $13/24$. Where is my failure?