-2 5/12 + х=-3 7/15
х=-3 7/15-(-2 5/12)
х=-3 7/15+2 5/12
х=-1 1/20
проверка:
-2 5/12 -1 1/20=-3 7/15
-3 7/15=-3 7/15
х= -3 7/15+2 5/12
х= -52/15+29/12
х= -208/60+145/60
х= -63/60
х= -21/20
х= -1 2/20
