(m-2)/(m^2-m-2) - m/(m^2+2m+1)=((m-2)(m+2)^2 - m(m^2-m-2)) / (m^2-m-2)(m+2)^2 = ((m^2-4)(m+2) - m^3+m^2+2m) / (m^2-m-2)(m+2)^2 =
(m^3+2m^2-4m-8 - m^3+m^2+2m) / (m^2-m-2)(m+2)^2 = (3m^2-2m-8) / (m^2-m-2)(m+2)^2 = (m-2)(m+4/3) / (m+1)(m-2)(m+2)^2 =(m+4/3) / (m+1)(m+2)^2