Answer:
x = 3
Step-by-step explanation:
Mathematically, the mean is the sum of the numbers divided by the count of the numbers
The count of the numbers is 5
Thus;
( 4 + 8 + 9 + x + 2x)/5 = 6
(21 + 3x)/5 = 6
21 + 3x = 6(5)
21 + 3x = 30
3x = 30-21
3x = 9
x = 9/3
x = 3
