Answer:
5 and -5
Step-by-step explanation:
Opposite numbers are the same distance from 0 on the number line. So, each of the numbers is a distance from zero that is half the distance between them.
The numbers are 10/2 = 5, and -5.
1: 14 ft
2: 18
3: 11; 28
4: 8; 96
5: a = 5x3
6: a = 8x8
7: 1x42, 2x21, 3x14, and 6x7. 6x7 probably makes the most sense.