Answer:
x= 10
Step-by-step explanation:
Mean is the sum of all values divided their number
(8.5+ 9 + 7.5 + 6 + 7 +x) / 6 = 8
(8.5+ 9 + 7.5 + 6 + 7 +x) = 8*6 = 48
(8.5+ 9 + 7.5 + 6 + 7 +x) =48
(38 +x) = 48
x= 48-38 = 10