Answer
(a) (-1, 5]
(b) (-$\infty$, 3)
(c) (4, $\infty$]
Work Step by Step
Looking at problem (a) it shows {$\mathcal{x}$ | -1 $\lt$ $\mathcal{x}$ $\leq$ 5} = (-1, 5]
Meaning that -1 is an open interval and 5 is a closed interval. This would include numbers between 0 and 5. The number -1 is not included because it is a closed interval.