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.
Answer:
-6 - square root 31, -6 + square root 31
The mass lost by Darragh's coin is 0.164 g
<u>Solution:</u>
Given that Darragh has a Golden Eagle coin in his collection with a mass of 13.551 g
An uncirculated Golden Eagle coin has a mass of 13.715 g
To find: mass lost by Darragh's coin
From given question,
Darrangh has coin of mass = 13.551 g
Golden Eagle coin mass = 13.715 g
Darrangh's coin lost mass = 13.715 - 13.551 = 0.164
Thus mass lost by Darragh's coin is 0.164 g