Solve for y.
y-1/y+1 = a-b/a+b

a. y=a/b
b. y=a-b/a+b
c. y=a+b/a-b

divide the numerator and denominator of right side of your equation to b then it would be (a/b)-1/(a/b)+1. so it becomes similar to left side. so y=a/b.

from the figure we get,

the x axis shows   the months and,

the y-axis shows the number of satisfied customer.

each line or each cell in upward direction (y-axis) shows 500.

the appropriate scale for the y - axis is: -

a = 2000 customers

b = 4000 customers

c = 6000 customers

d = 8000 customers

e = 10000 customers

f = 12000 customers

g = 14000 customers