To find the magnitude of a vector, take the components, square them, then add them, then take the square root. This is very similar to the Pythagorean Theorem.
For your particular problem, I’ve included a picture showing how that specific calculation is done. :)
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
Answer:
x= 3/4
Step-by-step explanation:
Step 1: Simplify both sides of the equation.
5x−2(x+1)=
1
/4
5x+(−2)(x)+(−2)(1)=
1
/4
(Distribute)
5x+−2x+−2=
1
/4
(5x+−2x)+(−2)=
1
/4
(Combine Like Terms)
3x+−2=
1
/4
3x−2=1
/4
Step 2: Add 2 to both sides.
3x−2+2=
1
/4
+2
3x=
9
/4
Step 3: Divide both sides by 3.
3x/
3
=
9
/4
/3
x=
3
/4