[m/(m^2-2m+1) - (m+2)/(m^2+m-2)]:1/(2m-2)^2=
=[m/(m-1)^2 - (m+2)/(m+2)(m-1)]*4(m-1)^2/[((m-1)^2) *(m+2)]=
=[m^2+2m-m^2-m+2]*4/(m+2)=(m+2)*4/(m+2)=4
[m/(m^2-2m+1) - (m+2)/(m^2+m-2)]:1/(2m-2)^2=
=[m/(m-1)^2 - (m+2)/(m+2)(m-1)]*4(m-1)^2/[((m-1)^2) *(m+2)]=
=[m^2+2m-m^2-m+2]*4/(m+2)=(m+2)*4/(m+2)=4