There are 3 coefficents. There is one in 6a, which is 6, one in 8z, which is 8, and one in 1/2n, which is 1/2.
Hope this helps, Ngam123!
-4x + 2x = -2x
6 + 5 = 11
Therefore, 11 - 2x = 0
11 = 2x
x = 11/2 = 5.5
Perimeter is 2(2x+5)+2(x-2) which is 4x+10+2x-4 which is in turn 6x+6. 6x+6 is the perimeter. Hope I helped!