isom (х-1+2)/(х-1) - 6/(х-1)(х+1) = 3(х-1)/(х+1)(х-1)
(х+1)(х-1)-6 / (х-1)(х+1) = (х²-х-3)/(х-1)(х+1)
(х²+х+х+1-6-3х+3)/(х-1)(х+1) = х²-х-3 / (х-1)(х+1) = (х+1)(х-3) / (х-1)(х+1) = х-3 / х-1