When you represent intervals on the number line, you're including full dots, excluding empty dots, and you're considering numbers highlighted by the line.
In the first case, you've highlighted everything before -2 (full dot, thus included), and everything after 1 (empty dot, excluded). So, the set would be

or, in interval notation,
![(-\infty,-2]\cup (1,\infty)](https://tex.z-dn.net/?f=%28-%5Cinfty%2C-2%5D%5Ccup%20%281%2C%5Cinfty%29)
In the second case, you are looking for all numbers between -3 and 5. This interval is symmetric with respect to 1: you're considering all numbers that are at most 4 units away from 1, both to the left and to the right.
This means that the difference between your numbers at 1 must be at most 4, which is modelled by

where the absolute values guarantees that you'll pick numbers to the left and to the right of 1.
X=2 because when you multiply 8 x 2=16 - 4=12
8(2)-4=12
First try it out yourself then compare answers. Remember, all squares have the same length per each side.
a) 3025
b) 25300
The range for the cities in the south is 145 larger than the range for the cities in the north.
We find the range by subtracting the highest and lowest values; in the North, we have:
305 - 58 = 247
In the South, we have:
503 - 111 = 392
The difference in the ranges is 392 - 247 = 145.