A is false but R is true (the mean of the last 3 values is not 8 since x=7)
The answer would be 20 or 9
3.14 by 3.57 just divide those numbers by 14 and round to the hundredths place
If solving for x you will first need to combine like terms. Then after getting the amount of numbers and amount of x numbers you will divide the x number from both. After doing that you would get X=-10
There is no solution. Here is the explanation with both of the methods :)