Выражение (1/b-1-1/b2-b)*b/b+2-2b/b2-

1) 1/(b-1) - 1/(b²-b) = 1/(b-1) - 1/(b(b-1)) = (b-1)/(b(b-1)) = 1/b
2) 1/b * b/(b+2) = 1/(b+2)
3) 1/(b+2) - 2b/(b²-4) = 1/(b+2) - 2b/((b-2)(b+2)) = (b-2-2b)/((b-2)(b+2)) = -(b+2)/((b-2)(b+2)) = - 1/(b-2)