retype with brackets to establish the correct order of operation.
did you mean
(3b-2)/b+1 = (4-b+2)/(b-1) or
3b - 2/(b+1) = 4-b + 2/b-1 or ...
still not totally clear, I will assume you mean
so the LCD is (b-1)(b-1), let's multiply each term by that
(3b-2)(b-1) = 4(b-1)(b+1) - (b+2)(b+1)
for which I go
b = 4