x2-y2-3x-3y/x-y-3 сократить дробь

x²-y²-3x-3= (х²-у²)-(3х+3у)=(х-у)(х+у)-3*(х+у)= (х+у)(х-у-3)

x²-y²-3x-3y/x-y-3 = (х+у)(х-у-3)/x-y-3 = х+у