Answer :
[tex](a + 2b + 3c) - (4a + 6b - 5c)= a + 2b + 3c- 4a-6b + 5c =\\ \\=- 3a - 4b + 8c[/tex]
(a + 2b + 3 c) - (4a + 6b - 5c) =
= a + 2b + 3c - 4a - 6b + 5c =
= -3a - 4b + 8c
= a + 2b + 3c - 4a - 6b + 5c =
= -3a - 4b + 8c