So first, you get the absolute value to one side:

Next, set up two equations; One where the value inside the absolute value lines is positive, and another where it is negative, and solve both for the variable:

Your answers are
8 and -8, or +-8.
Hello from MrBillDoesMath!
Answer:
27
Discussion:
By the distance formula (or Pythagorean theorem)
distance = sqrt ( (change in x)^2 + (change in y)^2)
In our case this becomes
distance = sqrt ( (18 - (-9) )^2 + (-12 - ( -12))^2)
= sqrt ( ( 18 + 9) ^2 + ( -12 + 12) ^ 2)
= sqrt ( ( 18 + 9) ^2 + 0^2 )
= sqrt ( 27^2)
= 27
Geometrically, as both y coordinates = -12, the points define a horizontal line segment. The length is then simply the difference of the x coordinates, 18 - (-9) = 18 +9 = 27. Same answer as before
Thank you,
MrB
There are two real roots (5 and -5) and 4 imaginary roots
Answer + Step-by-step explanation:
(a)
Check the attached image.
(b)
Range of sample means : 7.5 - 5.75 = 1.25
(c)
The closer the range of the sample means is to 0 ,
the more confident they can be in their estimate . 
The farther the range of the sample means is from 0 ,
the more confident they can be in their estimate .
The mean of the sample means will tend to be a better estimate
than a single sample mean . 
A single sample mean will tend to be a better estimate
than the mean of the sample means .
Honestly I don’t get the question