Answer :
firstly multiply the 8 by (n-10)
8(n-10) = 8n-80
form equation
(8n-80)/11 = 64
multiply both sides by 11
8n - 80 = 64 x 11
8n - 80 = 704
than add 80 to both sides
8n - 80 + 80 = 704 + 80
8n = 784
divide both sides by 8
8n/8 = 784/8
n = 98
8(n-10) = 8n-80
form equation
(8n-80)/11 = 64
multiply both sides by 11
8n - 80 = 64 x 11
8n - 80 = 704
than add 80 to both sides
8n - 80 + 80 = 704 + 80
8n = 784
divide both sides by 8
8n/8 = 784/8
n = 98