Answer
[-9,9]
Work Step by Step
First, multiply both ends of the inequality by 2 to cancel out the 2. Then subtract each side by 1 to get x by itself. Because the signs are less/greater than or equal to, x is or in between -9 and 9, and the brackets indicate that.
-4$\leq$$\frac{x+1}{2}$$\leq$5
-8$\leq$$x$+1$\leq$10
-9$\leq$$x$$\leq$9
[-9,9]