The 21 part repeats
it can be represented as 21/99
it's rational
Y + 7 = 3x.....y = 3x - 7
6x - 2y = 12
6x - 2(3x - 7) = 12
6x - 6x + 14 = 12
14 = 12 (incorrect)
when ur variables cancel out and u r left with an incorrect statement, this means there is no solution because ur lines are parallel
so ur answer is : no solution
Answer:
The age of the person who entered the room is 15
Step-by-step explanation:
We are given:
Ages of 5 people in a room are:
17, 16, 15, 17, 22
A person enters room, and then the mean age of 6 people is 17.
We need to find the age of person who entered the room.
The formula to calculate mean is: 
Now, in question we are given mean of 6 people that is 17
The age of 5 people are given while age of one person who enters the room is unknown.
Let age of person whose age is unknown= x
Now finding x using mean formula

So, The value of x: x=15
Hence, the age of the person who entered the room is 15
I think the answer is 8.7332602....I hope I helped!