Hi, this is the notation for inclusion of all real
numbers.

We can also state numbers which are positive or negative with a sign on top of the R notation like so:
Answer:
C
Step-by-step explanation:
y=1/x, the reciprocal is the same. Reciprocal would be reflected across y=x
I added a screenshot with the complete question
Answer:x = 3
y = 9
Explanation:1- getting the value of x:We are given that:
side AB is congruent to side DF. This means that:
AB = DF
3(2x+10) = 12x + 12
6x + 30 = 12x + 12
12x - 6x = 30 - 12
6x = 18
x = 18/6
x = 3
2- getting the value of y:We are given that:
side BC is congruent to side FG. This means that:
BC = FG
2y + 12 = 2(2y-3)
2y + 12 = 4y - 6
4y - 2y = 12 + 6
2y = 18
y = 18/2
y = 9
Hope this helps :)
Through the muscle contractions, or A
The answer to this problem is b