3 х+15 2 3х*(х+3)- х*(х+15) - 2(х²-9)
--------- - ----------- - ------- = -------------------------------------- =
х-3 х²-9 х (х-3)(х+3)х
3х²+9х- х²*-15х - 2х²+18 18-6х -6(х-3)
= -------------------------------------- = ---------------- = ------------------- =
(х-3)(х+3)х (х-3)(х+3)х (х-3)(х+3)х
-6
= -------------
(х+3)х