Variance of a continuous random variable X is defined as
Standard deviation is defined as

Hence standard deviation is the positive square root of variance.
Answer:
x = -7
Step-by-step explanation:
5x+8=3x-6
Subtract 3x from each side
5x-3x+8=3x-3x-6
2x+8 = -6
Subtract 8 from each side
2x+8-8 = -6-8
2x = -14
Divide by 2
2x/2 = -14/2
x = -7
Answer:
137.12
Step-by-step explanation:
Density = mass/volume
Density = 3.51
Mass = 481.3
Thus: 481.3/3.51 = 137.122507123
Answer:
try 5
Step-by-step explanation:
Answer:
The man is 27 years old.
Step-by-step explanation:
You can create a system of equations.
Let x = the age of the man
Let y = the age of his son
You can create the following equations based on what was given in the problem:
1. x = y + 18
2. (x - 3) = 4(y - 3)
You can simplify the second equation:
x - 3 = 4y - 12
x = 4y - 9
Then, solve the system of equations:
x = y + 18
-
x = 4y - 9
____________
0 = -3x + 27
The son's age is 9, therefore the father is 27 years old.